Fabrication and Characterization of Microneedle Patches for Loading and Delivery of Exosomes

Summary

Exosomes possess significant clinical potential, but their practical application is limited due to easy in vivo clearance and poor stability. Microneedles present a solution by enabling localized delivery by puncturing physiological barriers and dry-state preservation, thereby addressing the limitations of exosome administration and expanding their clinical utility.

Abstract

Exosomes, as emerging "next-generation" biotherapeutics and drug delivery vectors, hold immense potential in diverse biomedical fields, ranging from drug delivery and regenerative medicine to disease diagnosis and tumor immunotherapy. However, the rapid clearance by traditional bolus injection and poor stability of exosomes restrict their clinical application. Microneedles serve as a solution that prolongs the residence time of exosomes at the administration site, thereby maintaining the drug concentration and facilitating sustained therapeutic effects. In addition, microneedles also possess the ability to maintain the stability of bioactive substances. Therefore, we introduce a microneedle patch for loading and delivering exosomes and share the methods, including isolation of exosomes, fabrication, and characterization of exosome-loaded microneedle patches. The microneedle patches were fabricated using trehalose and hyaluronic acid as the tip materials and polyvinylpyrrolidone as the backing material through a two-step casting method. The microneedles demonstrated robust mechanical strength, with tips able to withstand 2 N. Pig skin was used to simulate human skin, and the tips of microneedles completely melted within 60 s after skin puncture. The exosomes released from the microneedles exhibited morphology, particle size, marker proteins, and biological functions comparable to those of fresh exosomes, enabling dendritic cells uptake and promoting their maturation.

Introduction

Exosomes, which are small vesicles released by cells into the extracellular matrix, have been proposed as potential biotherapeutics and drug delivery vectors for the treatment of several diseases and cancers¹. During their biogenesis process, exosomes encapsulate various biologically active molecules from within the cells, including functional proteins and nucleic acids². As a result, when taken up by recipient cells during the transport process, exosomes have the ability to modulate gene expression and cellular functions in the target cells³. As a kind of natural information messenger, exosomes h....

Protocol

This study does not require ethical clearance as the pig skin used for the experiments described in section 3 was purchased as edible pig ears from the market and not sourced from experimental animals.

1. Isolation of exosomes

1. Cell culture
   1. Cultivate mouse ovarian epithelial cancer cells ID8 in Dulbecco's Modified Eagle Medium (DMEM) culture medium containing 10% fetal bovine serum and 1% penicillin-streptomycin solution (100×) (see Tabl.......

Discussion

Currently, the main methods for isolating exosomes include ultracentrifugation, density-gradient centrifugation, ultrafiltration, precipitation, immunoaffinity magnetic beads, and microfluidics²⁴. Due to the limited loading capacity of microneedles caused by their small needle tip space, it is necessary to increase the concentration of exosomes to load more. Therefore, we chose ultrafiltration to concentrate the cell culture supernatant and then used ultracentrifugation to isolate the exosomes. Th.......

Materials

Name	Company	Catalog Number	Comments
100x penicillin-streptomycin solutions	Jrunbio Scientific	MA0110	Cell culture
180 kDa pre-stained protein marker	Thermo	26616	Western blotting
3% Uranyl acetate	Henan Ruixin Experimental Supplies	GZ02625	Morphological characterization of exosomes
3D printer	BMF technology	nanoArch S130	Mold preparation
4%–20% precast gel	Genscript	ExpressPlus PAGE GEL	Western blotting
5× SDS-PAGE loading buffer	Titan	04048254	Western blotting
Anti-mouse Alix antibody	Biolegend	12422-1-AP	Western blotting
Anti-mouse CD63 antibody	Biolegend	ab217345	Western blotting
APC anti-mouse CD80 antibody	Biolegend	104713	Antibody
Auto fine coater	ZIZHU	JBA5-100	Morphological characterization of microneedle
BCA assay kit	Beyotime	P0012	Protein concentration assay
Centrifuge	Thermo Fisher	Muitifuge X1R pro	Cell centrifuge
Circulating water vacuum pump	Yuhua Instrument	SHZ-D(III)	Filtration
CO2 incubator	Eppendorf	CellXpert C170	Cell culture
Confocal laser scanning microscope	Nikon	A1HD25	Fluorescence imaging
Copper mesh	Beijing Zhongjingkeyi Technology	JF-ZJKY/300	Morphological characterization of exosomes
D- (+) -Trehalose dihydrate	Aladdin	5138-23-4	Fabrication of microneedle
Dulbecco’s modified Eagle’s medium	Meilunbio	MA0212	Cell culture
Dulbecco’s phosphate-buffered saline	Meilunbio	MA0010	Cell culture
Electrophoresis system	Bio-rad	PowerPac-basic	Western blotting
Fetal bovine serum	Jrunbio Scientific	JR100	Cell culture
FITC anti-mouse CD11c antibody	Biolegend	117305	Antibody
Flow cytometry	BD	LSR Fortessa	Fluorescence detection
Gel imager	Cytiva	Amersham ImageQuant 800	Western blotting
HRP-conjugated anti-rabbit IgG	CST	7074S	Western blotting
HTL resin	BMF technology		Mold preparation
Hyaluronic acid (MW = 300 kDa)	Bloomage Biotechnology	9004-61-9	Fabrication of microneedle
Immersion oil	Nikon	MXA22168	Fluorescence imaging
Ion cleaner	JEOL	EC-52000IC	Morphological characterization of exosomes
Microscope	Olympus	CKX53	Observe the microneedle tip dissolving process
Mouse ovarian epithelial cancer cell ID8	MeisenCTCC	CC90105	Cell culture
Nanoparticle tracking analysis	Particle Metrix	ZetaView	Size analysis of exosomes
Pacific Blue anti-mouse I-A/I-E antibody	Biolegend	107619	Antibody
Phenylmethanesulfonyl fluoride	Beyotime	ST507	Protease inhibitors
Plasma cleaner	Hefei Kejing Material Technology	PDC-36G	Fabrication of microneedle
Polydimethylsiloxane	Dow Corning	9016-00-6	Mold preparation
Polyvinylpyrrolidone (MW = 40 kDa)	Aladdin	9003-39-8	Fabrication of microneedle
Prism	GraphPad	Version 9	Statistical analysis
PVDF membrane	Millipore	IPVH00010	Western blotting
Quick-snap centrifuge	Beckman	344619	Exosomes extraction
RIPA lysis buffer	Applygen	C1053	Lysis membrane
Roswell park memorial institute 1640	Meilunbio	MA0548	Cell culture
Scanning electron microscope	JEOL	JSM-IT800	Morphological characterization of microneedle
Stereo microscope	Olympus	SZX16	Characterization of morphology
Super ECL detection reagent	Applygen	P1030	Western blotting
Tensile meter	Instron	68SC-05	Mechanical testing
Transmission electron microscope	JEOL	JEM-2100plus	Morphological characterization of exosomes
Tris buffered saline	Sangon Biotech	JF-A500027-0004	Western blotting
Tween-20	Beyotime	ST825	Western blotting
Ultracentrifuge	Beckman	Optima XPN-100	Exosomes extraction
Ultrafiltration tube	Millipore	UFC910096	Exosomes concentration
Vacuum drying oven	Shanghai Yiheng Technology	DZF-6024	Fabrication of microneedle
Vacuum filtration system	Biosharp	BS-500-XT	Filtration