Targeting therapy for hepatocellular carcinoma by delivering microRNAs as exosomal cargo

Exosomes,the smallest extracellular vesicles,have gained significant attention as key mediators in intercellular communication,influencing both physiological and pathological processes,particularly in cancer progression.A recent review article by Wang et al was published in a timely manner to stimulate future research and facilitate practical developments for targeted treatment of hepatocellular carcinoma using exosomes,with a focus on the origin from which exosomes derive.If information about the mechanisms for delivering exosomes to specific cells is incorporated,the concept of targeted therapy for hepatocellular carcinoma using exosomes could be more comprehensively understood.

A food-grade and senescent cell-targeted fisetin delivery system based on whey protein isolate-galactooligosaccharides Maillard conjugate

Cellular senescence is the results of aging and age-related diseases,and the development of anti-aging methods may improve health and extend longevity.The natural flavonol fisetin has been shown to antagonize senescence in vitro and increases longevity in vivo,but has poor water solubility and limited bioavailability.In this study,a food-grade and senescent cell-targeted delivery system for fisetin was developed based on whey protein isolate-galactooligosaccharides(WPI-GOS)Maillard conjugate,which could recognize senescence associatedβ-galactosidase in senescent cells.The fisetin nanoparticles possessed a high encapsulation efficiency,excellent dispersibility in water,good storage stability and well biocompatibility.Moreover,they could effectively accumulate and retain in senescent cells with excellent senescent cell-targeting efficacy,and inhibit the oxidative stress-induced cellular senescence in vitro.Thus,this novel nanoparticle system based on WPI-GOS Maillard conjugate showed promise to deliver hydrophobic bioactive ingredients like fisetin to senescent cells to improve their bioavailability and anti-senescence effect.

In Situ Synthesis of Fluorescent Mesoporous Silica–Carbon Dot Nanohybrids Featuring Folate Receptor-Overexpressing Cancer Cell Targeting and Drug Delivery

Multifunctional nanocarrier-based theranostics is supposed to overcome some key problems in cancer treatment.In this work,a novel method for the preparation of a fluorescent mesoporous silica–carbon dot nanohybrid was developed.Carbon dots(CDs),from folic acid as the raw material,were prepared in situ and anchored on the surface of amino-modified mesoporous silica nanoparticles(MSNs–NH2) via a microwave-assisted solvothermal reaction.The as-prepared nanohybrid(designated MSNs–CDs) not only exhibited strong and stable yellow emission but also preserved the unique features of MSNs(e.g.,mesoporous structure,large specific surface area,and good biocompatibility),demonstrating a potential capability for fluorescence imagingguided drug delivery.More interestingly,the MSNs–CDs nanohybrid was able to selectively target folate receptor-overexpressing cancer cells(e.g.,HeLa),indicating that folic acid still retained its function even after undergoing the solvothermal reaction.Benefited by these excellent properties,the fluorescent MSNs–CDs nanohybrid can be employed as a fluorescence-guided nanocarrier for the targeted deliveryof anticancer drugs(e.g.,doxorubicin),thereby enhancing chemotherapeutic efficacy and reducing side effects.Our studies may provide a facile strategy for the fabrication of multifunctional MSN-based theranostic platforms,which is beneficial in the diagnosis and therapy of cancers in future.

Intranasal delivery of paeoniflorin nanocrystals for brain targeting

Paeoniflorin(PA) is an anti-Parkinson Chinese medicine with inferior bioavailability and difficulty in delivery to the brain. This research is to develop an efficacious PA nanocrystal formulation(PA-NCs) that is suitable for intranasal administration to treat Parkinson’s disease(PD). PA-NCs were fabricated through an antisolvent precipitation method using TPGS as the stabilizer. The rod-shaped PA-NCs had particle size of 139.6 ± 1.3 nm and zeta potential of-23.2 ± 0.529 mV. A molecular dynamics simulation indicated that van der Waals forces are the primary drivers of interactions between PA and TPGS. In the ex vivo nasal mucosa permeation assay, the cumulative drug release at 24 h was 87.14% ± 5.34%,which was significantly higher than that of free PA. PA-NCs exhibited substantially improved cellular uptake as well as permeability on Calu-3 cells as compared to PA alone. FRET imaging analysis demonstrated that intact NCs could be internalized into Calu-3 cells.Moreover, PA-NCs conferred desirable protective effect against MPP+-induced SH-SY5Y cellular damage. Pharmacokinetic studies revealed a higher PA concentration in the brain following intranasal delivery of PA-NCs. In summary, the intranasal administration of PANCs is a promising treatment strategy for PD.

Synthesis of a novel multivalent galactoside with high hepatocyte targeting for gene delivery

A novel bifunctional glycolipid which carded a cluster of thiogalactosides as the hepatocyte targeting ligand for gene delivery was prepared. Hexa-antennary alcohol 1 was used as the core scaffold to attach a cholesterol molecule by a poly（ethylene glycol） chain, while its remaining branches were linked with five acetylgalactosides, which would be deacetylated later to produce pentaantennary galactoside. Liposome containing the galactoside showed high affinity and transfection activity in hepatoma cells HepG2.

Brain delivering RNA-based therapeutic strategies by targeting mTOR pathway for axon regeneration after central nervous system injury

Injuries to the central nervous system(CNS)such as stroke,brain,and spinal cord trauma often result in permanent disabilities because adult CNS neurons only exhibit limited axon regeneration.The brain has a surprising intrinsic capability of recovering itself after injury.However,the hostile extrinsic microenvironment significantly hinders axon regeneration.Recent advances have indicated that the inactivation of intrinsic regenerative pathways plays a pivotal role in the failure of most adult CNS neuronal regeneration.Particularly,substantial evidence has convincingly demonstrated that the mechanistic target of rapamycin(mTOR)signaling is one of the most crucial intrinsic regenerative pathways that drive axonal regeneration and sprouting in various CNS injuries.In this review,we will discuss the recent findings and highlight the critical roles of mTOR pathway in axon regeneration in different types of CNS injury.Importantly,we will demonstrate that the reactivation of this regenerative pathway can be achieved by blocking the key mTOR signaling components such as phosphatase and tensin homolog(PTEN).Given that multiple mTOR signaling components are endogenous inhibitory factors of this pathway,we will discuss the promising potential of RNA-based therapeutics which are particularly suitable for this purpose,and the fact that they have attracted substantial attention recently after the success of coronavirus disease 2019 vaccination.To specifically tackle the blood-brain barrier issue,we will review the current technology to deliver these RNA therapeutics into the brain with a focus on nanoparticle technology.We will propose the clinical application of these RNA-mediated therapies in combination with the brain-targeted drug delivery approach against mTOR signaling components as an effective and feasible therapeutic strategy aiming to enhance axonal regeneration for functional recovery after CNS injury.

A novel gene delivery system targeting cells expressing VEGF receptors

Two ligand oligopeptides GV1 and GV2 were designed according to the putative binding region of VEGF to its receptors. GV1, GV2 and endosome releasing oligopeptide HA20 were conjugated with poly-L-lysine or protamine and the resulting conjugates could interact with DNA in a noncovalent bond to form a complex. Using pSV2-β-galactosidase as a reporter gene, it has been demonstrated that exogenous gene was transferred into bovine aortic arch-derived endothelial cells (ABAE) andhuman malignant melanoma cell lines (A375) in vitro. In vivo experiments, exogenous gene was transferred into tumor vascular endothelial cells and tumor cells of subcutaneously transplanted human colon cancer LOVO, human malignant melanoma A375 and human hepatoma graft in nude mice. This system could also target gene to intrahepatically transplanted human hepatoma injected via portal vein in nude mice. These results are correlated with theGene delivery system targeting VEGF receptors relevant receptors (flt-1, flk-1/KDR) expression on the targeted cells and tissues.

Recent advances in zwitterionic nanoscale drug delivery systems to overcome biological barriers

Nanoscale drug delivery systems(nDDS)have been employed widely in enhancing the therapeutic efficacy of drugs against diseases with reduced side effects.Although several nDDS have been successfully approved for clinical use up to now,biological barriers between the administration site and the target site hinder the wider clinical adoption of nDDS in disease treatment.Polyethylene glycol(PEG)-modification(or PEGylation)has been regarded as the gold standard for stabilising nDDS in complex biological environment.However,the accelerated blood clearance(ABC)of PEGylated nDDS after repeated injections becomes great challenges for their clinical applications.Zwitterionic polymer,a novel family of antifouling materials,have evolved as an alternative to PEG due to their super-hydrophilicity and biocompatibility.Zwitterionic nDDS could avoid the generation of ABC phenomenon and exhibit longer blood circulation time than the PEGylated analogues.More impressively,zwitterionic nDDS have recently been shown to overcome multiple biological barriers such as nonspecific organ distribution,pressure gradients,impermeable cell membranes and lysosomal degradation without the need of any complex chemical modifications.The realization of overcoming multiple biological barriers by zwitterionic nDDS may simplify the current overly complex design of nDDS,which could facilitate their better clinical translation.Herein,we summarise the recent progress of zwitterionic nDDS at overcoming various biological barriers and analyse their underlyingmechanisms.Finally,prospects and challenges are introduced to guide the rational design of zwitterionic nDDS for disease treatment.

Dual ligand-targeted Pluronic P123 polymeric micelles enhance the therapeutic effect of breast cancer with bone metastases

Bone metastasis secondary to breast cancer negatively impacts patient quality of life and survival.The treatment of bone metastases is challenging since many anticancer drugs are not effectively delivered to the bone to exert a therapeutic effect.To improve the treatment efficacy,we developed Pluronic P123(P123)-based polymeric micelles dually decorated with alendronate(ALN)and cancer-specific phage protein DMPGTVLP(DP-8)for targeted drug delivery to breast cancer bone metastases.Doxorubicin(DOX)was selected as the anticancer drug and was encapsulated into the hydrophobic core of the micelles with a high drug loading capacity(3.44%).The DOX-loaded polymeric micelles were spherical,123 nm in diameter on average,and exhibited a narrow size distribution.The in vitro experiments demonstrated that a pH decrease from 7.4 to 5.0 markedly accelerated DOX release.The micelles were well internalized by cultured breast cancer cells and the cell death rate of micelle-treated breast cancer cells was increased compared to that of free DOX-treated cells.Rapid binding of the micelles to hydroxyapatite(HA)microparticles indicated their high affinity for bone.P123-ALN/DP-8@DOX inhibited tumor growth and reduced bone resorption in a 3D cancer bone metastasis model.In vivo experiments using a breast cancer bone metastasis nude model demonstrated increased accumulation of the micelles in the tumor region and considerable antitumor activity with no organ-specific histological damage and minimal systemic toxicity.In conclusion,our study provided strong evidence that these pH-sensitive dual ligand-targeted polymeric micelles may be a successful treatment strategy for breast cancer bone metastasis.

Hydrodynamic modeling of ferrofluid flow in magnetic targeting drug delivery

Among the proposed techniques for delivering drugs to specific locations within human body, magnetic drug targeting prevails due to its non-invasive character and its high targeting efficiency. Magnetic targeting drug delivery is a method of carrying drug-loaded magnetic nanoparticles to a target tissue target under the applied magnetic field. This method increases the drug concentration in the target while reducing the adverse side-effects. Although there have been some theoretical analyses for magnetic drug targeting, very few researchers have addressed the hydrodynamic models of magnetic fluids in the blood vessel. A mathematical model is presented to describe the hydrodynamics of ferrofiuids as drug carriers flowing in a blood vessel under the applied magnetic field. In this model, magnetic force and asymmetrical force are added, and an angular momentum equation of magnetic nanoparticles in the applied magnetic field is modeled. Engineering approximations are achieved by retaining the physically most significant items in the model due to the mathematical complexity of the motion equations. Numerical simulations are performed to obtain better insight into the theoretical model with computational fluid dynamics. Simulation results demonstrate the important parameters leading to adequate drug delivery to the target site depending on the magnetic field intensity, which coincident with those of animal experiments. Results of the analysis provide important information and suggest strategies for improving delivery in clinical application.

Process Modeling of Ferrofluids Flow for Magnetic Targeting Drug Delivery

Among the proposed techniques for delivering drugs to specific sites within the human body, magnetic targeting drug delivery surpasses due to its non-invasive character and its high targeting efficiency. Although there have been some analyses theoretically for magnetic drug targeting, very few researchers have addressed the hydrodynamic models of magnetic fluids in the blood vessel of human body. This paper presents a mathematical model to describe the hydrodynamics of ferrofluids as drug carriers flowing in a blood vessel under the applied magnetic field. A 3D flow field of magnetic particles in a blood vessel model is numerically simulated in order to further understand clinical application of magnetic targeting drug delivery. Simulation results show that magnetic nanoparticles can be enriched in a target region depending on the applied magnetic field intensity. Magnetic resonance imaging confirms the enrichment of ferrofluids in a desired body tissue of Sprague-Dawley rats. The simulation results coincide with those animal experiments. Results of the analysis provide the important information and can suggest strategies for improving delivery in favor of the clinical application.

pH-sensitive polymeric nanocarriers for antitumor biotherapeutic molecules targeting delivery

pH-sensitive smart polymeric nanocarriers have been under development in the field ofbiomedicine due to permeabilization the physiological barriers readily to address the limitation of conventional chemotherapeutics delivery systems of low intracellular transport and targeting efficiency.Where traditional polymers kept stable under physiological neutral or acidic conditions,pH-sensitive polymeric nanocarriers underwent rapid degradation with a labile group in tumor acidic environment(around 5.0-6.0),allowing these biomaterials to achieve controlled drug release,drug pharmacokinetics improvement and antitumor biotherapeutic molecules efficiency enhancement compared with traditional polymers.This review mainly concentrated on properties of pH-sensitive polymers for biomedical purposes to construct the smart drug delivery system based on acid liable linkers which were categorized into pH-sensitive polymeric prodrugs composed of antitumor drugs(doxorubicin and paclitaxel)bounded to the polymer via acid liable linkers and pH-sensitive copolymeric nanocarriers prepared by block copolymers containing polymer blocks linked with acid-cleavable groups.Besides,advanced platforms in biomedicine for special biotherapeutic molecules delivery were reviewed in the article.Furthermore,several acid-sensitive linkages were reviewed to study the mechanism of the controlled pH-responsive drug delivery,such as hydrazone,acetal,cis-aconityl linker and β-thioether ester,as well as improvement of drug pharmacokinetics.

Receptor-mediated gene delivery using polyethylenimine (PEI) coupled with polypeptides targeting FGF receptors on cells surface

Objective: To construct a novel kind of nonviral gene delivery vector based on polyethylenimine (PEI) conjugated with polypeptides derived from ligand FGF with high transfection efficiency and according to tumor targeting ability. Methods: The synthetic polypeptides CR16 for binding FGF receptors was conjugated to PEI and the characters of the polypeptides in-cluding DNA condensing and particle size were determined. Enhanced efficiency and the targeting specificity of the synthesized vector were investigated in vitro and in vivo. Results: The polypeptides were successfully coupled to PEI. The new vectors PEI-CR16 could efficiently condense pDNA into particles with around 200 nm diameter. The PEI-CR16/pDNA polyplexes showed significantly greater transgene activity than PEI/pDNA in FGF receptors positive tumor cells in vitro and in vivo gene transfer, while no difference was observed in FGF receptors negative tumor cells. The enhanced transfection efficiency of PEI-CR16 could be blocked by excess free polypeptides. Conclusion: The synthesized vector could improve the efficiency of gene transfer and targeting specificity in FGF receptors positive cells. The vector had good prospect for use in cancer gene therapy.

Nanoparticles for targeted delivery of therapeutics and small interfering RNAs in hepatocellular carcinoma

Hepatocellular carcinoma(HCC) is the 5th most common malignancy which is responsible for more than half million annual mortalities; also, it is the third leading cause of cancer related death. Unfavorablesystemic side-effects of chemotherapeutic agents and susceptibility to the degradation of small interfering RNAs(si RNAs), which can knock down a specific gene involved in the disease, have hampered their clinical application. So, it could be beneficial to develop an efficient carrier for the stabilization and specific delivery of drugs and si RNA to cells. Targeted nanoparticles have gained considerable attention as an efficient drug and gene delivery system, which is due to their capability in achieving the highest accumulation of cytotoxic agents in tumor tissue, modifiable drug pharmacokinetic- and bio-distribution, improved effectiveness of treatment, and limited sideeffects. Recent studies have shed more light on the advantages of novel drug loaded carrier systems vs free drugs. Most of the animal studies have reported improvement in treatment efficacy and survival rate using novel carrier systems. Targeted delivery may be achieved passively or actively. In passive targeting, no ligand as homing device is used, while targeting is achieved by incorporating the therapeutic agent into a macromolecule or nanoparticle that passively reaches the target organ. However, in active targeting, the therapeutic agent or carrier system is conjugated to a tissue or cell-specific receptor which is overexpressed in a special malignancy using a ligand called a homing device. This review covers a broad spectrum of targeted nanoparticles as therapeutic and nonviral si RNA delivery systems, which are developed for enhanced cellular uptake and targeted gene silencing in vitro and in vivo and their characteristics and opportunities for the clinical applications of drugs and therapeutic si RNA are discussed in this article. Asialoglycoprotein receptors, low-density lipoprotein, ganglioside GM1 cell surface ligand, epidermal growth factor receptor receptors, monoclonal antibodies, retinoic acid receptors, integrin receptors targeted by Arg-Gly-Asp peptide, folate, and transferrin receptors are the most widely studied cell surface receptors which are used for the site specific delivery of drugs and si RNA-based therapeutics in HCC and discussed in detail in this article.

Elaborately engineering of lipid nanoparticle for targeting delivery of siRNA and suppressing acute liver injury

Small interfering RNA(siRNA)-based gene silencing has been considered as a potential therapy modality against inflammatory diseases.Nevertheless,the effective delivery of siRNA to desired destination still remains challenging due to poor stability,high molecular weight and negative charge.Currently,ionizable lipid nanoparticle(LNP)has been extensively used as vector for effective delivery of siRNA.Herein,we report a mannose-modified LNP(M-MC_(3) LNP@TNFα)loading tumor necrosis factorα(TNFα)siRNA for targeting liver macrophages,achieving effectively inhibit acute liver injury.The M-MC_(3) LNP@TNFαnot only increases the internalization of LNP by macrophages,but also enhances the gene silencing efficiency of TNFαin vitro.Additionally,the M-MC_(3) LNP@TNFαexhibits higher accumulation in liver of healthy mice than that of MC_(3) LNP@TNFα(un-modified LNP)owing to the targeting effect of mannose.As expected,the M-MC_(3) LNP@TNFαsignificantly suppresses the expression of TNFαand ameliorates liver damage in acute liver injury model.Such a LNP targeting siRNA delivery holds great potential for the treatment of diseases associated with liver in the future.

Micromanaging cardiac regeneration:Targeted delivery of micro RNAs for cardiac repair and regeneration

The loss of cardiomyocytes during injury and disease can result in heart failure and sudden death, while the adult heart has a limited capacity for endogenous regeneration and repair. Current stem cell-based regenerative medicine approaches modestly improve cardiomyocyte survival, but offer neglectable cardiomyogenesis. This has prompted the need for methodological developments that crease de novo cardiomyocytes. Current insights in cardiac development on the processes and regulatory mechanisms in embryonic cardiomyocyte differentiation provide a basis to therapeutically induce these pathways to generate new cardiomyocytes. Here, we discuss the current knowledge on embryonic cardiomyocyte differentiation and the implementation of this knowledge in state-ofthe-art protocols to the direct reprogramming of cardiac fibroblasts into de novo cardiomyocytes in vitro and in vivo with an emphasis on micro RNA-mediated reprogramming. Additionally, we discuss current advances on state-of-theart targeted drug delivery systems that can be employed to deliver these micro RNAs to the damaged cardiac tissue. Together, the advances in our understanding of cardiac development, recent advances in micro RNAbased therapeutics, and innovative drug delivery systems, highlight exciting opportunities for effective therapies for myocardial infarction and heart failure.

Drug-targeting methodologies with applications: A review

Targeted drug delivery to solid tumors is a very active research area, focusing mainly on improved drug formulation and associated best delivery methods/devices. Drug-targeting has the potential to greatly improve drug-delivery efficacy, reduce side effects, and lower the treatment costs. However, the vast majority of drug-targeting studies assume that the drug-particles are already at the target site or at least in its direct vicinity. In this review, drug-delivery methodologies, drug types and drug-delivery devices are discussed with examples in two major application areas:(1) inhaled drug-aerosol delivery into human lung-airways; and(2) intravascular drug-delivery for solid tumor targeting. The major problem addressed is how to deliver efficiently the drug-particles from the entry/infusion point to the target site. So far, most experimental results are based on animal studies. Concerning pulmonary drug delivery, the focus is on the pros and cons of three inhaler types, i.e., pressurized metered dose inhaler, dry powder inhaler and nebulizer, in addition to drug-aerosol formulations. Computational fluid-particle dynamics techniques and the underlying methodology for a smart inhaler system are discussed as well.Concerning intravascular drug-delivery for solid tumor targeting, passive and active targeting are reviewed as well as direct drug-targeting, using optimal delivery of radioactive microspheres to liver tumors as an example. The review concludes with suggestions for future work, considereing both pulmonary drug targeting and direct drug delivery to solid tumors in the vascular system.

Recent strategies on targeted delivery of thrombolytics

Thrombus formed in blood vessel is a progressive process, which would lead to lifethreatening thrombotic diseases such as ischemic stroke. Unlike other diseases, the recognition of thrombus is usually in the late stage where blood vessels are largely blocked. So acute thrombotic diseases have a narrow therapeutic window, and remain leading causes of morbidity and mortality, whereas current thrombolysis therapy has limited therapeutic effects and bleeding complications. Thrombolytic agents in unwanted sites would cause hemorrhage due to the activation of plasminogen. Moreover, untargeted thrombolysis therapy require large amounts of thrombolytic agents, which in return would enhance hemorrhage risk. To improve the efficiency while minimizing the adverse effects of traditional thrombolysis therapy, novel drug delivery systems have been investigated. Various targeting strategies including ultrasound and magnetic field directed targeting, and specific binding, have been designed to deliver thrombolytic drugs to the thrombotic sites. These strategies demonstrate promising results in reducing bleeding risk as well as allowing less dosage of thrombolytic drugs with lowered clot lysis time. In this review, we discuss recent progress on targeted delivery of thrombolytics, and summarize treatment advantages and shortcomings, potentially helping to further promote the development of targeted thrombolysis.

In Vitro Targeted Magnetic Delivery and Tracking of Superparamagnetic Iron Oxide Particles Labeled Stem Cells for Articular Cartilage Defect Repair

To assess a novel cell manipulation technique of tissue engineering with respect to its ability to augment superparamagnetic iron oxide particles （SPIO） labeled mesenchymal stem cells （MSCs） density at a localized cartilage defect site in an in vitro phantom by applying magnetic force. Meanwhile, non-invasive imaging techniques were use to track SPIO-labeled MSCs by magnetic resonance imaging （MRI）. Human bone marrow MSCs were cultured and labeled with SPIO. Fresh degenerated human osteochondral fragments were obtained during total knee arthroplasty and a cartilage defect was created at the center. Then, the osteochondral fragments were attached to the sidewalls of culture flasks filled with phosphate-buffered saline （PBS） to mimic the human joint cavity. The SPIO-labeled MSCs were injected into the culture flasks in the presence of a 0.57 Tesla （T） magnetic force. Before and 90 min after cell targeting, the specimens underwent T2-weighted turbo spin-echo （SET2WI） sequence of 3.0 T MRI. MRI results were compared with histological findings. Macroscopic observation showed that SPIO-labeled MSCs were steered to the target region of cartilage defect. MRI revealed significant changes in signal intensity （P0.01）. HE staining exibited that a great number of MSCs formed a three-dimensional （3D） cell ＂sheet＂ structure at the chondral defect site. It was concluded that 0.57 T magnetic force permits spatial delivery of magnetically labeled MSCs to the target region in vitro. High-field MRI can serve as an very sensitive non-invasive technique for the visualization of SPIO-labeled MSCs.

Development of PLGA micro-and nanorods with high capacity of surface ligand conjugation for enhanced targeted delivery

Particle shape has been recognized as one of the key properties of nanoparticles in biomedical applications including targeted drug delivery.Targeting ability of shape-engineered particles depends largely on targeting ligands conjugated on the particle surface.However,poor capacity for surface ligand conjugation remains a problem in anisotropic nanoparticles made with biodegradable polymers such as PLGA.In this study,we prepared anisotropic PLGA nanoparticles with abundant conjugatable surface functional groups by a film stretching-based fabrication method with poly(ethylene-alt-maleic acid)(PEMA).Scanning electron microscopy images showed that microrods and nanorods were successfully fabricated by the PEMA-based film stretching method.The presence of surface carboxylic acid groups was confirmed by confocal microscopy and zeta potential measurements.Using the improved film-stretching method,the amount of protein conjugated to the surface of nanorods was increased three-fold.Transferrin-conjugated,nanorods fabricated by the improved method exhibited higher binding and internalization than unmodified counterparts.Therefore,the PEMA-based film-stretching system presented in this study would be a promising fabrication method for non-spherical biodegradable polymeric micro-and nanoparticles with high capacity of surface modifications for enhanced targeted delivery.