Functional microfluidics:theory,microfabrication,and applications

Microfluidic devices are composed of microchannels with a diameter ranging from ten to a few hundred micrometers.Thus,quite a small(10-9–10-18l)amount of liquid can be manipulated by such a precise system.In the past three decades,significant progress in materials science,microfabrication,and various applications has boosted the development of promising functional microfluidic devices.In this review,the recent progress on novel microfluidic devices with various functions and applications is presented.First,the theory and numerical methods for studying the performance of microfluidic devices are briefly introduced.Then,materials and fabrication methods of functional microfluidic devices are summarized.Next,the recent significant advances in applications of microfluidic devices are highlighted,including heat sinks,clean water production,chemical reactions,sensors,biomedicine,capillaric circuits,wearable electronic devices,and microrobotics.Finally,perspectives on the challenges and future developments of functional microfluidic devices are presented.This review aims to inspire researchers from various fields engineering,materials,chemistry,mathematics,physics,and more—to collaborate and drive forward the development and applications of functional microfluidic devices,specifically for achieving carbon neutrality.

Nanotechnology for diagnosis and therapy of theumatoid arthritis:Evolution towards theranostic approaches

Rheumatoid arthritis(RA),as a chronic autoimmune disease,damages the bone and cartilage of patients,and even leads to disability.Therefore,the diagnosis and treatment of RA is particularly important.However,due to the complexity of RA,it is difficult to make effective early diagnosis of RA,which is detrimental to RA treatment.Besides,long-term intake of anti-RA drugs can also cause damage to patients' organs.The emergence of nanotechnology provides the new train of thoughts for the diagnosis and treatment of RA.And the combination of diagnosis and therapy is an ideal method to solve the problem of disease management of RA patients.In this review,we summarize the mechanism and microenvironment of RA,discuss the commonly used diagnostic techniques and therapeutic drugs for RA,and review their advantages and disadvantages.New nanotherapy strategies such as drug-carrying nanoparticles,PTT,PDT are listed,and their applications in RA treatment are also summarized.In addition,multimodal imaging,combined therapy and responsive diagnosis and treatment are also summarized as important contents.At last,we also review typical nanocarriers that can be used in the integration of diagnosis and therapy,and discussed their potential applications in RA theranostics.

Facile synthesis and in vivo bioimaging applications of porphyrin derivative-encapsulated polymer nanoparticles

Fluorescence(FL)imaging guided photodynamic therapy(PDT)is becoming highly desirable for personalized therapy and precision medicine.In this study,fluorescent polymer nanoparticles TCPP@PEI/PGA were facilely synthesized through electrostatic interaction-mediated self-assembly of porphyrins tetra(4-carboxyphenyl)porphine(TCPP)and polyethylenimine(PEI),and subsequent surface modification withγ-poly(glutamic acid)(γ-PGA).TCPP served a dual function as the FL imaging probe and the photosensitizer.The as-prepared TCPP@PEI/PGA nanoparticles showed excellent water-solubility and biocompatibility,while having outstanding capabilities of in vivo bioimaging and~1 O_(2) generation.FL bioimaging of mice and effective killing of CT 26 cells as well as CT 26 tumor-bearing mice upon laser irradiation were successfully demonstrated when using TCPP@PEI/PGA as theranostic nanoprobes.This study provides a simple but robust method to design and synthesize porphyrin-based polymer nanoparticles for theranostics.

A Design of Single-Switch Two-Stage DC-DC Converters With PWM And PFM for Off-Grid Solar Power System

In this paper,a single-switch two-stage DC-DC conversion circuit is proposed for an off-grid solar power application.A photovoltaic(PV)panel powers the load and a storage unit(battery)via the proposed circuit.The battery is designed to balance the supply and the demand of power under different irradiation situations.Based on conventional cascaded DC-DC converters,the proposed design is developed with the single switch technique reducing size,cost and power loss.The control scheme in this design is pulse width modulation(PWM)with pulse frequency modulation(PFM).The PWM module is similar to conventional design except its ramp signal with a variable frequency is provided by a resettable integrator.As a result,the PWM and PFM modules regulate the two stages of the proposed circuit separately with the same switching control signal.In this paper,the modes of operation of the circuit are discussed as well as the control schemes.The design process is described along with the circuit analysis and comparisons with conventional design are made as well.A prototype has been built to verify the proposed circuit with simulation and experimental results.