Microfluidics for nano-drug delivery systems: From fundamentals to industrialization

In recent years,owing to the miniaturization of the fluidic environment,microfluidic technology offers unique opportunities for the implementation of nano drug delivery systems(NDDSs)production processes.Compared with traditional methods,microfluidics improves the controllability and uniformity of NDDSs.The fast mixing and laminar flow properties achieved in the microchannels can tune the physicochemical properties of NDDSs,including particle size,distribution and morphology,resulting in narrow particle size distribution and high drug-loading capacity.The success of lipid nanoparticles encapsulated mRNA vaccines against coronavirus disease 2019 by microfluidics also confirmed its feasibility for scaling up the preparation of NDDSs via parallelization or numbering-up.In this review,we provide a comprehensive summary of microfluidics-based NDDSs,including the fundamentals of microfluidics,microfluidic synthesis of NDDSs,and their industrialization.The challenges of microfluidicsbased NDDSs in the current status and the prospects for future development are also discussed.We believe that this review will provide good guidance for microfluidics-based NDDSs.

The role of caveolin-1 in the biofate and efficacy of anti-tumor drugs and their nano-drug delivery systems

As one of the most important components of caveolae,caveolin-1 is involved in caveolaemediated endocytosis and transcytosis pathways,and also plays a role in regulating the cell membrane cholesterol homeostasis and mediating signal transduction.In recent years,the relationship between the expression level of caveolin-1 in the tumor microenvironment and the prognostic effect of tumor treatment and drug treatment resistance has also been widely explored.In addition,the interplay between caveolin-1 and nano-drugs is bidirectional.Caveolin-1 could determine the intracellular biofate of specifc nano-drugs,preventing from lysosomal degradation,and facilitate them penetrate into deeper site of tumors by transcytosis;while some nanocarriers could also affect caveolin-1 levels in tumor cells,thereby changing certain biophysical function of cells.This article reviews the role of caveolin-1 in tumor prognosis,chemotherapeutic drug resistance,antibody drug sensitivity,and nano-drug delivery,providing a reference for the further application of caveolin-1 in nano-drug delivery systems.

Gather wisdom to overcome barriers:Well-designed nano-drug delivery systems for treating gliomas

Due to the special physiological and pathological characteristics of gliomas,most therapeutic drugs are prevented from entering the brain.To improve the poor prognosis of existing therapies,researchers have been continuously developing non-invasive methods to overcome barriers to gliomas therapy.Although these strategies can be used clinically to overcome the blood-brain barrier(BBB),the accurate delivery of drugs to the glioma lesions cannot be ensured.Nano-drug delivery systems(NDDS)have been widely used for precise drug delivery.In recent years,researchers have gathered their wisdom to overcome barriers,so many well-designed NDDS have performed prominently in preclinical studies.These meticulous designs mainly include cascade passing through BBB and targeting to glioma lesions,drug release in response to the glioma microenvironment,biomimetic delivery systems based on endogenous cells/extracellular vesicles/protein,and carriers created according to the active ingredients of traditional Chinese medicines.We reviewed these well-designed NDDS in detail.Furthermore,we discussed the current ongoing and completed clinical trials of NDDS for gliomas therapy,and analyzed the challenges and trends faced by clinical translation of these well-designed NDDS.

Delivering Microrobots in the Musculoskeletal System

Disorders of the musculoskeletal system are the major contributors to the global burden of disease and current treatments show limited efficacy.Patients often suffer chronic pain and might eventually have to undergo end-stage surgery.Therefore,future treatments should focus on early detection and intervention of regional lesions.Microrobots have been gradually used in organisms due to their advantages of intelligent,precise and minimally invasive targeted delivery.Through the combination of control and imaging systems,microrobots with good biosafety can be delivered to the desired area for treatment.In the musculoskeletal system,microrobots are mainly utilized to transport stem cells/drugs or to remove hazardous substances from the body.Compared to traditional biomaterial and tissue engineering strategies,active motion improves the efficiency and penetration of local targeting of cells/drugs.This review discusses the frontier applications of microrobotic systems in different tissues of the musculoskeletal system.We summarize the challenges and barriers that hinder clinical translation by evaluating the characteristics of different microrobots and finally point out the future direction of microrobots in the musculoskeletal system.

Ionizable drug delivery systems for efficient and selective gene therapy

Gene therapy has shown great potential to treat various diseases by repairing the abnormal gene function.However,a great challenge in bringing the nucleic acid formulations to the market is the safe and effective delivery to the specific tissues and cells.To be excited,the development of ionizable drug delivery systems(IDDSs)has promoted a great breakthrough as evidenced by the approval of the BNT162b2 vaccine for prevention of coronavirus disease 2019(COVID-19)in 2021.Compared with conventional cationic gene vectors,IDDSs can decrease the toxicity of carriers to cell membranes,and increase cellular uptake and endosomal escape of nucleic acids by their unique pH-responsive structures.Despite the progress,there remain necessary requirements for designing more efficient IDDSs for precise gene therapy.Herein,we systematically classify the IDDSs and summarize the characteristics and advantages of IDDSs in order to explore the underlying design mechanisms.The delivery mechanisms and therapeutic applications of IDDSs are comprehensively reviewed for the delivery of plasmid DNA(pDNA)and four kinds of RNA.In particular,organ selecting considerations and high-throughput screening are highlighted to explore efficiently multifunctional ionizable nanomaterials with superior gene delivery capacity.We anticipate providing references for researchers to rationally design more efficient and accurate targeted gene delivery systems in the future,and indicate ideas for developing next generation gene vectors.

Mesenchymal stem cells-based drug delivery systems for diabetic foot ulcer:A review

The complication of diabetes,which is known as diabetic foot ulcer(DFU),is a significant concern due to its association with high rates of disability and mortality.It not only severely affects patients’quality of life,but also imposes a substantial burden on the healthcare system.In spite of efforts made in clinical practice,treating DFU remains a challenging task.While mesenchymal stem cell(MSC)therapy has been extensively studied in treating DFU,the current efficacy of DFU healing using this method is still inadequate.However,in recent years,several MSCs-based drug delivery systems have emerged,which have shown to increase the efficacy of MSC therapy,especially in treating DFU.This review summarized the application of diverse MSCs-based drug delivery systems in treating DFU and suggested potential prospects for the future research.

Recent progress of respiratory inhalation drug delivery systems

With the influence of many factors such as the aging of the population,the younger smokers,and the serious air pollution,the incidence of chronic respiratory diseases is increasing year by year.In the treatment of respiratory diseases,clinical intervention is still mainly based on drug control of pulmonary symptoms.However,systemic drugs have disadvantages such as many adverse reactions and severe systemic side effects.In recent years,the research and development of local drug delivery systems for the respiratory tract has brought new changes to the treatment of respiratory diseases.Locally delivered drugs can directly act on the airways and have the characteristics of fast onset,good curative effect and small side effects.It is a simple,efficient and safe treatment method,which has a very significant effect,and has become a hot topic of current research and promotion.This paper briefly reviews the development track and latest research progress of respiratory local drug delivery systems at home and abroad,in order to provide reference for clinical workers in drug selection and application.

Charcoal Nanoparticles as a Delivery System for Doxorubicin and Sorafenib in Treatment of Hepatocellular Carcinoma

Background: Hepatocellular carcinoma (HCC) is the most common type of liver cancer and one of the leading causes of cancer-related death worldwide. Advanced HCC displays strong resistance to chemotherapy, and traditional chemotherapy drugs do not achieve satisfactory therapeutic efficacy. The delivery of therapeutic compounds to the target site is a major challenge in the treatment of many diseases. Objective: This study aims to evaluate activated charcoal nanoparticles as a drug delivery system for anticancer agents (Sorafenib and Doxorubicin) in Hepatocellular Cancer Stem Cells. Method: The percent efficiency of entrapment (% EE) of the doxorubicin and sorafenib entrapped onto the activated charcoal was obtained by determining the free doxorubicin and sorafenib concentration in the supernatant-prepared solutions. Then the characterizations of nanoparticles were formed by determination of the particle size distribution, zeta potential, and polydispersity index (PDI). The anticancer activity of activated Charcoal, Doxorubicin-ACNP, sorafenib-ACNP, free doxorubicin, and free sorafenib solutions was measured based on cell viability percentage in HepG2 cell lines (ATCC-CCL 75). In vitro RBC’s toxicity of Doxorubicin/sorafenib loaded charcoal was estimated by hemolysis percentage. Results: The synthesized Doxorubicin-ACNP and Sorafenib-ACNP were evaluated and their physiochemical properties were also examined. Essentially, the percent Efficiency of Entrapment (EE %) was found to be 87.5% and 82.66% for Doxorubicin-ACNP and Sorafenib-ACNP, respectively. The loading capacity was 34.78% and 24.31% for Doxorubicin-ACNP and Sorafenib-ACNP. Using the Dynamic Light scattering [DLS] for the determination of the hydrodynamic size and surface zeta potential, a narrow sample size distribution was obtained of (18, 68, and 190 nm for charcoal, 105, 255, and 712 nm for doxorubicin, and 91, 295, and 955 nm for sorafenib), respectively. A surface charge of −13.2, −15.6 and −17 was obtained for charcoal, doxorubicin/charcoal, and sorafenib/charcoal nanoparticles. The cytotoxic activity of Doxorubicin-ACNP and Sorafenib-ACNP was evaluated in-vitro against HepG2 cell lines and it was observed that Drug loaded ACNP improved anticancer activity when compared to Doxorubicin or Sorafenib alone. Moreover, testing the toxicity potential of DOX-ACNP and Sorafenib-ACNP showed a significant reduction in the hemolysis of red blood cells when compared to Doxorubicin and Sorafenib alone. Conclusion: In conclusion, it is notable to state that this study is regarded as the first to investigate the use of Activated charcoal for the loading of Doxorubicin and Sorafenib for further use in the arena of hepatocellular carcinoma. Doxorubicin-ACNP and Sorafenib-ACNP showed noteworthy anticancer activity along with a reduced potential of RBCs hemolysis rendering it as an efficacious carrier with a low toxicity potential.

Variability and Correlation in Biomarkers of Exposure from Two Randomized Controlled Studies of JUUL Electronic Nicotine Delivery Systems

The data included in this analysis were from two clinical studies (Study A and Study B), which evaluated JUUL electronic nicotine delivery systems (ENDS) against combustible cigarettes. In both studies, biomarkers of exposure including nicotine equivalents, NNAL, 3-HPMA, MHBMA, S-PMA and COHb were measured. Coefficients of variation (CV) of the biomarkers were calculated and compared. Pearson correlation analysis was used to examine the correlation between the biomarkers. Seven out of the nine biomarkers of exposure in Study A were highly variable (CV > 30%). Higher variability was observed in NNAL, MHBMA and S-PMA than in other biomarkers. After adult cigarette smokers switched from combustible cigarettes to JUUL ENDS, the correlation between nicotine equivalents and other biomarkers became weaker. A similar trend was observed between NNAL and other biomarkers. In Study B, the participants in the 5% ENDS group had higher nicotine equivalent levels than those in the 3% ENDS group. The higher nicotine levels did not result in a substantial increase in the levels of other biomarkers (except 1-OHP). The correlations between nicotine equivalents and 3-HPMA, MHBMA, S-PMA, COHb, HMPMA, and 1-OHP were weak in both the 5% and 3% ENDS groups.

A review on phospholipids and their main applications in drug delivery systems

Phospholipids have the characteristics of excellent biocompatibility and a especial amphiphilicity.These unique properties make phospholipids most appropriate to be employed as important pharmaceutical excipients and they have a very wide range of applications in drug delivery systems.The aim of this review is to summarize phospholipids and some of their related applications in drug delivery systems,and highlight the relationship between the properties and applications,and the effect of the species of phospholipids on the efficiency of drug delivery.We refer to some relevant literatures,starting from the structures,main sources and properties of phospholipids to introduce their applications in drug delivery systems.The present article focuses on introducing five types of carriers based on phospholipids,including liposomes,intravenous lipid emulsions,micelles,drug-phospholipids complexes and cochleates.

Reliable transmission of consultative committee for space data systems file delivery protocol in deep space communication

In consultative committee for space data systems（CCSDS） file delivery protocol（CFDP） recommendation of reliable transmission,there are no detail transmission procedure and delay calculation of prompted negative acknowledge and asynchronous negative acknowledge models.CFDP is designed to provide data and storage management,story and forward,custody transfer and reliable end-to-end delivery over deep space characterized by huge latency,intermittent link,asymmetric bandwidth and big bit error rate（BER）.Four reliable transmission models are analyzed and an expected file-delivery time is calculated with different trans-mission rates,numbers and sizes of packet data units,BERs and frequencies of external events,etc.By comparison of four CFDP models,the requirement of BER for typical missions in deep space is obtained and rules of choosing CFDP models under different uplink state informations are given,which provides references for protocol models selection,utilization and modification.

Delivery systems for siRNA drug development in cancer therapy

Since the discovery of the Nobel prize-winning mechanism of RNA interference(RNAi)ten years ago,it has become a promising drug target for the treatment of multiple diseases,including cancer.There have already been some successful applications of siRNA drugs in the treatment of age-related macular degeneration and respiratory syncytial virus infection.However,significant barriers still exist on the road to clinical applications of siRNA drugs,including poor cellular uptake,instability under physiological conditions,off-target effects and possible immunogenicity.The successful application of siRNA for cancer therapy requires the development of clinically suitable,safe and effective drug delivery systems.Herein,we review the design criteria for siRNA delivery systems and potential siRNA drug delivery systems for cancer therapy,including chemical modifications,lipidbased nanovectors,polymer-mediated delivery systems,conjugate delivery systems,and others.

Development of nanoscale drug delivery systems of dihydroartemisinin for cancer therapy: A review

Dihydroartemisinin(DHA),a first-line antimalarial drug,has demonstrated great anticancer effects in many types of tumors,including liver cancer,glioblastoma,and pancreatic cancer.Due to its abilities to induce programmed cell death(PCD;apoptosis,autophagy and ferroptosis),inhibit tumor metastasis and angiogenesis,and modulate the tumor microenvironment,DHA could become an antineoplastic agent in the foreseeable future.However,the therapeutic efficacy of DHA is compromised owing to its inherent disadvantages,including poor stability,low aqueous solubility,and short plasma halflife.To overcome these drawbacks,nanoscale drug delivery systems(NDDSs),such as polymeric nanoparticles(NPs),liposomes,and metal-organic frameworks(MOFs),have been introduced to maximize the therapeutic efficacy of DHA in either single-drug or multidrug therapy.Based on the beneficial properties of NDDSs,including enhanced stability and solubility of the drug,prolonged circulation time and selective accumulation in tumors,the outcomes of DHA-loaded NDDSs for cancer therapy are significantly improved compared to those of free DHA.This reviewfirst summarizes the current understanding of the anticancer mechanisms of DHA and then provides an overview of DHA-including nanomedicines,aiming to provide inspiration for further application of DHA as an anticancer drug.

pH-responsive mesoporous silica nanoparticles employed in controlled drug delivery systems for cancer treatment

In the fight against cancer, controlled drug delivery systems have emerged to enhance the therapeutic efficacy and safety of anti-cancer drugs. Among these systems, mesoporous silica nanoparticles （MSNs） with a functional surface possess obvious advantages and were thus rapidly developed for cancer treatment. Many stimuli-responsive materials, such as nanopartides, polymers, and inorganic materials, have been applied as caps and gatekeepers to control drug release from MSNs. This review presents an overview of the recent progress in the production of pH-responsive MSNs based on the pH gradient between normal tissues and the tumor microenvironment. Four main categories of gatekeepers can respond to acidic conditions. These categories will be described in detail.

Electrospun nanofiber-based drug delivery systems

Electrospinning is a very simple and versatile process by which polymer nanofibers with di-ameters ranging from a few nanometers to sev-eral micrometers can be produced using an electrostatically driven jet of polymer solution or polymer melt. Significant progress has been made in this process throughout the past few years and electrospinning has advanced its ap-plications in many fields, including pharmaceu-tics. Electrospun nanofibers show great prom-ise for developing many types of novel drug delivery systems (DDS) due to their special characteristics and the simple but useful and effective top-down fabricating process. The current state of electrospun nanofiber-based DDS is focused on drug-loaded nanofiber preparation from pharmaceutical and biode-gradable polymers and different types of DDS. However, there are more opportunities to be exploited from the electrospinning process and the corresponding drug-loaded nanofibers for drug delivery. Additionally, some other related challenges and the possible resolutions are outlined in this review.

From oral formulations to drug-eluting implants:using 3D and 4D printing to develop drug delivery systems and personalized medicine

Since the start of the Precision Medicine Initiative by the United States of America in 2015,interest in personalized medicine has grown extensively.In short,personalized medicine is a term that describes medical treatment that is tuned to the individual.One possible way to realize personalized medicine is 3D printing.When using materials that can be tuned upon stimulation,4D printing is established.In recent years,many studies have been exploring a new field that combines 3D and 4D printing with therapeutics.This has resulted in many concepts of pharmaceutical devices and formulations that can be printed and,possibly,tailored to an individual.Moreover,the first 3D printed drug,Spritam®,has already found its way to the clinic.This review gives an overview of various 3D and 4D printing techniques and their applications in the pharmaceutical field as drug delivery systems and personalized medicine.

Novel drug delivery systems for inflammatory bowel disease

Inflammatory bowel disease(IBD)is a chronic illness characterized by relapsing inflammation of the intestines.The disorder is stratified according to the severity and is marked by its two main phenotypical representations:Ulcerative colitis and Crohn’s disease.Pathogenesis of the disease is ambiguous and is expected to have interactivity between genetic disposition,environmental factors such as bacterial agents,and dysregulated immune response.Treatment for IBD aims to reduce symptom extent and severity and halt disease progression.The mainstay drugs have been 5-aminosalicylates(5-ASAs),corticosteroids,and immunosuppressive agents.Parenteral,oral and rectal routes are the conventional methods of drug delivery,and among all,oral administration is most widely adopted.However,problems of systematic drug reactions and low specificity in delivering drugs to the inflamed sites have emerged with these regular routes of delivery.Novel drug delivery systems have been introduced to overcome several therapeutic obstacles and for localized drug delivery to target tissues.Enteric-coated microneedle pills,various nano-drug delivery techniques,prodrug systems,lipid-based vesicular systems,hybrid drug delivery systems,and biologic drug delivery systems constitute some of these novel methods.Microneedles are painless,they dislodge their content at the affected site,and their release can be prolonged.Recombinant bacteria such as genetically engineered Lactococcus Lactis and eukaryotic cells,including GM immune cells and red blood cells as nanoparticle carriers,can be plausible delivery methods when evaluating biologic systems.Nano-particle drug delivery systems consisting of various techniques are also employed as nanoparticles can penetrate through inflamed regions and adhere to the thick mucus of the diseased site.Prodrug systems such as 5-ASAs formulations or their derivatives are effective in reducing colonic damage.Liposomes can be modified with both hydrophilic and lipophilic particles and act as lipid-based vesicular systems,while hybrid drug delivery systems containing an internal nanoparticle section for loading drugs are potential routes too.Leukosomes are also considered as possible carrier systems,and results from mouse models have revealed that they control anti-and pro-inflammatory molecules.

Transdermal drug delivery systems in diabetes management: A review

Diabetes mellitus is a chronic disease in which there is an insufficient production of insulin by the pancreas, or the insulin produced is unable to be utilized effectively by the body. Diabetes affects more than 415 million people globally and is estimated to strike about 642 million people in 2040. The WHO reported that diabetes will become the seventh biggest cause of mortality in 2030. Insulin injection and oral hypoglycemic agents remain the primary treatments in diabetes management. These often present with poor patient compliance. However, over the last decade, transdermal systems in diabetes management have gained increasing attention and emerged as a potential hope in diabetes management owing to the advantages that they offer as compared to invasive injection and oral dosage forms. This review presents the recent advances and developments in transdermal research to achieve better diabetes management. Different technologies and approaches have been explored and applied to the transdermal systems to optimize diabetes management. Studies have shown that these transdermal systems demonstrate higher bioavailability compared to oral administration due to the avoidance of first-pass hepatic metabolism and a sustained drug release pattern. Besides that, transdermal systems have the advantage of reducing dosing frequency as drugs are released at a predetermined rate and control blood glucose level over a prolonged time, contributing to better patient compliance. In summary, the transdermal system is a field worth exploring due to its significant advantages over oral route in administration of antidiabetic drugs and biosensing of blood glucose level to ensure better clinical outcomes in diabetes management.

Delivery of therapeutics to posterior eye segment:cell-encapsulating systems

Drug delivery to the posterior segment of the eye, especially the retina, faces the unique challenges of various anatomical and physiological barriers. Invasive intravitreal injection is currently the mainstream clinical approach to posterior eye diseases such as age-related macular degeneration, diabetic retinopathy, uveitis, and cytomegalovirus retinitis. Repeated injections could be complicated by endophthalmitis, intra- ocular pressure elevation, retinal vascular occlusion, and ret- inal detachment, let alone the psychological and economical burdens suffered by patients （Schwartz et al., 2014）. In view of this, several extended release drug delivery systems have been devised and the idea of encapsulated-cell technology （ECT） has gained popularity in recent decades since its first proposal in the 1960s.

Formulation of self-nanoemulsifying drug delivery systems containing monoacyl phosphatidylcholine and Kolliphor^(■) RH40 using experimental design

The development of self-nanoemulsifying drug delivery systems(SNEDDS) to enhance the oral bioavailability of lipophilic drugs is usually based on traditional one-factor-at-a-time approaches. These approaches may be inadequate to analyse the effect of each excipient and their potential interactions on the emulsion droplet size formed when dispersing the SNEDDS in an aqueous environment. The current study investigates the emulsion droplet sizes formed from SNEDDS containing different levels of the natural surfactant monoacyl phosphatidylcholine to reduce the concentration of the synthetic surfactant polyoxyl 40 hydrogenated castor oil(Kolliphor ~? RH40). Monoacyl phosphatidylcholine was used in the form of Lipoid S LPC 80(LPC, containing approximately 80% monoacyl phosphatidylcholine, 13% phosphatidylcholine and 4% concomitant components). The investigated SNEDDS comprised of long-chain or medium-chain glycerides(40% to 75%), Kolliphor ~? RH40(5% to 55%), LPC(0 to 40%) and ethanol(0 to 10%). D-optimal design, multiple linear regression, and partial least square regression were used to screen different SNEDDS within the investigated excipient ranges and to analyse the effect of each excipient on the resulting droplet size of the dispersed SNEDDS measured by dynamic light scattering. All investigated formulations formed nano-emulsions with droplet sizes from about 20 to 200 nm. The use of mediumchain glycerides was more likely to result in smaller and more monodisperse droplet sizes compared to the use of long-chain glycerides. Kolliphor~? RH40 exhibited the most significant effect on reducing the emulsion droplet sizes. Increasing LPC concentration increased the emulsion droplet sizes, possibly because of the reduction of Kolliphor~? RH40 concentration. A higher concentration of ethanol resulted in an insignificant reduction of the emulsion droplet size. The study provides different ternary diagrams of SNEDDS containing LPC and Kolliphor ~? RH40 as a reference for formulation developers.