Preparation and Characterization of Electrospun Colon-Specific Delivery System for Quercetin and Its Antiproliferative Effect on Cancer Cells

Effects of quercetin- and Lactiplantibacillus plantarum-containing bioactive films on physicochemical properties and microbial safety of grass carp

In this study, the electrospinning technique was used to co-encapsulate Quercetin (Qu) and Lactiplantibacillus plantarum 1-24-LJ in PVA-based nanofibers, and the effect of bioactive films on fish preservation was evaluated at the first time. The findings indicated that both Lpb. plantarum 1-24-LJ and Qu were successfully in the fibers, and co-loaded fibers considerably outperformed single-loaded fiber in terms of bacterial survival and antioxidant activity. Following fish preservation using the loaded fibers, significant reductions were observed in TVB-N, TBARS, and microbial complexity compared to the control group. Additionally, the co-loaded fibers more effectively reduced the counts of H2S-producing bacteria and Pseudomonas. In the future, fibers with both active substances and LAB hold promise as a novel approach for fish preservation.

Development of quercetin-loaded electrospun nanofibers through shellac coating on gelatin: Characterization, colon-targeted delivery, and anticancer activity

Quercetin possesses multiple biological activities. To achieve efficient colon-specific release of quercetin, new composite nanofibers were developed by coating pH-responsive shellac on hydrophilic gelatin through coaxial electrospinning. These composite nanofibers contained bead-like structures. The encapsulation efficiency (87.6-98.5 %) and loading capacity (1.4-4.1 %) varied with increasing the initial quercetin addition amount (2.5-7.5 %). FTIR, XRD, and TGA results showed that the quercetin was successfully encapsulated in composite nanofibers in an amorphous state, with interactions occurring among quercetin, gelatin, and shellac. Composite nanofibers had pH-responsive surface wettability due to the shellac coating. In vitro digestion experiments showed that these composite nanofibers were highly stable in the upper gastrointestinal tract, with quercetin release ranging from 4.75 % to 12.54 %. In vivo organ distribution and pharmacokinetic studies demonstrated that quercetin could be sustainably released in the colon after oral administration of composite nanofibers. Besides, the enhanced anticancer activity of composite nanofibers was confirmed against HCT-116 cells by analyzing their effect on cell viability, cell cycle, and apoptosis. Overall, these novel composite nanofibers could deliver efficiently quercetin to the colon and achieve its sustained release, thus potential to regulate colon health. This system is also helpful in delivering other bioactives to the colon and exerting their functional effects.

Applications of polysaccharides in enzyme-triggered oral colon-specific drug delivery systems: A review

Enzyme-triggered oral colon-specific drug delivery system (EtOCDDS1) can withstand the harsh stomach and small intestine environments, releasing encapsulated drugs selectively in the colon in response to colonic microflora, exerting local or systematic therapeutic effects. EtOCDDS boasts high colon targetability, enhanced drug bioavailability, and reduced systemic side effects. Polysaccharides are extensively used in enzyme-triggered oral colon-specific drug delivery systems, and its colon targetability has been widely confirmed, as their properties meet the demand of EtOCDDS. Polysaccharides, known for their high safety and excellent biocompatibility, feature modifiable structures. Some remain undigested in the stomach and small intestine, whether in their natural state or after modifications, and are exclusively broken down by colon-resident microbiota. Such characteristics make them ideal materials for EtOCDDS. This article reviews the design principles of EtOCDDS as well as commonly used polysaccharides and their characteristics, modifications, applications and specific mechanism for colon targeting. The article concludes by summarizing the limitations and potential of ETOCDDS to stimulate the development of innovative design approaches.

Wireless electrostimulation for cancer treatment: An integrated nanoparticle/coaxial fiber mesh platform

Cancer, namely breast and prostate cancers, is the leading cause of death in many developed countries. Controlled drug delivery systems are key for the development of new cancer treatment strategies, to improve the effectiveness of chemotherapy and tackle off-target effects. In here, we developed a biomaterials-based wireless electrostimulation system with the potential for controlled and on-demand release of anti-cancer drugs. The system is composed of curcumin-loaded poly(3,4-ethylenedioxythiophene) nanoparticles (CUR/PEDOT NPs), encapsulated inside coaxial poly(glycerol sebacate)/poly(caprolactone) (PGS/PCL) electrospun fibers. First, we show that the PGS/PCL nanofibers are biodegradable, which allows the delivery of NPs closer to the tumoral region, and have good mechanical properties, allowing the prolonged storage of the PEDOT NPs before their gradual release. Next, we demonstrate PEDOT/CUR nanoparticles can release CUR on-demand (65 % of release after applying a potential of -1.5 V for 180 s). Finally, a wireless electrostimulation platform using this NP/fiber system was set up to promote in vitro human prostate cancer cell death. We found a decrease of 67 % decrease in cancer cell viability. Overall, our results show the developed NP/fiber system has the potential to effectively deliver CUR in a highly controlled way to breast and prostate cancer in vitro models. We also show the potential of using wireless electrostimulation of drug-loaded NPs for cancer treatment, while using safe voltages for the human body. We believe our work is a stepping stone for the design and development of biomaterial-based future smarter and more effective delivery systems for anti-cancer therapy.

Advances and applications of crosslinked electrospun biomacromolecular nanofibers

Electrospinning is a technology for fabricating ultrafine fibers from natural or synthetic polymers that have novel or enhanced functional properties. These fibers have found applications in a diverse range of fields, including the food, medicine, cosmetics, agriculture, and chemical industries. However, the tendency for electrospun nanofibers to dissociate when exposed to certain environmental conditions limits many of their practical applications. The structural integrity and functional attributes of these nanofibers can be improved using physical and/or chemical crosslinking methods. This review article discusses the formation of polymeric nanofibers using electrospinning and then describes how different crosslinking methods can be used to enhance their mechanical, thermal, and biological attributes. Methods for optimizing the crosslinking reactions are discussed, including proper selection of crosslinker type and reaction conditions. Then, food, medical, and separation applications of crosslinked electrospun fibers are assessed, including in bone and skin tissue engineering, wound healing, drug delivery, air filtration, water filtration, oil removal, food packaging, food preservation, and bioactive delivery. Finally, areas where future research are needed are highlighted, as well as possible future applications of crosslinked nanofibers.

Preparation of Eudragit S100-pullulan/hydroxypropyl-β-cyclodextrin complex-Eudragit S100 multilayer nanofiber film for resveratrol colon delivery

Cyclodextrin-based electrospun nanofibers are promising for encapsulating and preserving unstable compounds, but quick dissolution of certain nanofibers hinders their delivery application. In this study, hydroxypropyl-β-cyclodextrin (HPβCD) was used as an effective carrier of resveratrol (RSV) to obtain the RSV/HPβCD inclusion complex (HPIC), which was then incorporated into pullulan nanofibers. For enhancement of RSV release toward colon target, multilayer structure with a pullulan/HPIC film sandwiched between two layers of hydrophobic Eudragit S100 (ES100) nanofibers was employed. The relationship between the superiority of the ES100-pullulan/HPIC-ES100 film and its multilayer structure was verified. The intimate interactions of hydrogen bonds between two adjacent layers enhanced thermal stability, and the hydrophobic outer layers improved water contact resistance. According to release results, multilayer films also showed excellent colon-targeted delivery property and approximately 78.58 % of RSV was observed to release in colon stage. In terms of release mechanism, complex mechanism best described RSV colonic release. Additionally, ES100-pullulan/HPIC-ES100 multilayer films performed higher encapsulation efficiency when compared to the structures without HPIC, which further increased the antioxidant activity and total release amount of RSV. These results suggest a promising strategy for designing safe colonic delivery systems based on multilayer and HPIC structures with superior preservation for RSV.

Fabrication of colon-targeted ethyl cellulose/gelatin hybrid nanofibers: Regulation of quercetin release and its anticancer activity

A colon-targeted delivery system that can efficiently deliver and release quercetin is essential to improve its bioavailability. We previously found that hydrophobic ethyl cellulose (EC) nanofibers could efficiently deliver quercetin to colon, but the release of quercetin was limited. To address this problem, hydrophilic gelatin (GN) was used as a regulator, and quercetin-loaded nanofibers with different mass ratios of EC to GN (3:1, 1:1, 1:2, 1:3) were fabricated by electrospinning. All nanofibers had a cylindrical morphology and high encapsulation efficiency (over 94 %), and there existed molecular interactions among quercetin, EC, and GN. The high GN content reduced the thermal stability of nanofibers but increased their surface wettability. Besides, these nanofibers had good stability in acidic and aqueous foods. Importantly, the release of quercetin in the simulated gastrointestinal fluid was <3 %. The addition of GN was beneficial to the release of quercetin in colon, and nanofibers with EC to GN being 1:3 had a more preferable release performance. The anticancer activity of nanofibers against HCT-116 cells was proved by inhibiting cell viability through the induction of apoptosis. Therefore, these nanofibers are potential carriers for efficient colon-targeted delivery of bioactive compounds in the food industry.

Electrospun fiber-based micro- and nano-system for delivery of high concentrated quercetin to cancer cells

The anticancer potential of quercetin (Q), a plant-derived flavonoid, and underlining molecular mechanisms are widely documented in cellular models in vitro. However, biomedical applications of Q are limited due to its low bioavailability and hydrophilicity. In the present study, the electrospinning approach was used to obtain polylactide (PLA) and PLA and polyethylene oxide (PEO)-based micro- and nanofibers containing Q, namely PLA/Q and PLA/PEO/Q, respectively, in a form of non-woven fabrics. The structure and physico-chemical properties of Q-loaded fibers were characterized by scanning electron and atomic force microscopy (SEM and AFM), X-ray powder diffraction (XRD), differential scanning calorimetry (DSC), goniometry and FTIR and Raman spectroscopy. The anticancer action of PLA/Q and PLA/PEO/Q was revealed using two types of cancer and nine cell lines, namely osteosarcoma (MG-63, U-2 OS, SaOS-2 cells) and breast cancer (SK-BR-3, MCF-7, MDA-MB-231, MDA-MB-468, Hs 578T, and BT-20 cells). The anticancer activity of Q-loaded fibers was more pronounced than the action of free Q. PLA/Q and PLA/PEO/Q promoted cell cycle arrest, oxidative stress and apoptotic cell death that was not overcome by heat shock protein (HSP)-mediated adaptive response. PLA/Q and PLA/PEO/Q were biocompatible and safe, as judged by in vitro testing using normal fibroblasts. We postulate that PLA/Q and PLA/PEO/Q with Q releasing activity can be considered as a novel and more efficient micro- and nano-system to deliver Q and eliminate phenotypically different cancer cells.

Encapsulation of quercetin into zein-ethyl cellulose coaxial nanofibers: Preparation, characterization and its anticancer activity

In order to efficiently improve the colon-targeted delivery of quercetin, the hydrophobic core-shell nanofibers were fabricated to encapsulate quercetin using ethyl cellulose as the shell and zein as the core by coaxial electrospinning. The encapsulation efficiency of coaxial nanofibers reached >97 %. FTIR and XRD results revealed the interactions between quercetin and wall materials and quercetin was encapsulated in an amorphous state. The thermal stability and surface hydrophobicity of coaxial nanofibers were improved compared to the uniaxial zein fibers. After in vitro gastrointestinal digestion, the quercetin release from core-shell nanofibers was <12.38 %, while the corresponding value for zein fibers was 36.24 %. DPPH and FRAP assays showed that there was no significant difference in the antioxidant activity of quercetin before and after encapsulation. Furthermore, the encapsulated quercetin exhibited similar anti-proliferative activity against HCT-116 cells compared to the free form. The results suggest these coaxial nanofibers have potential applications in functional foods.

Multi-material electrospinning: from methods to biomedical applications

Electrospinning as a versatile, simple, and cost-effective method to engineer a variety of micro or nanofibrous materials, has contributed to significant developments in the biomedical field. However, the traditional electrospinning of single material only can produce homogeneous fibrous assemblies with limited functional properties, which oftentimes fails to meet the ever-increasing requirements of biomedical applications. Thus, multi-material electrospinning referring to engineering two or more kinds of materials, has been recently developed to enable the fabrication of diversified complex fibrous structures with advanced performance for greatly promoting biomedical development. This review firstly gives an overview of multi-material electrospinning modalities, with a highlight on their features and accessibility for constructing different complex fibrous structures. A perspective of how multi-material electrospinning opens up new opportunities for specific biomedical applications, i.e., tissue engineering and drug delivery, is also offered.

Preparation of core-shell hordein/pectin nanoparticles as quercetin delivery matrices: Physicochemical properties and colon-specific release analyses

Quercetin (Que) is a hydrophobic flavanol that has the potential to prevent colon diseases. This study aimed to design hordein/pectin nanoparticle as a colon-specific delivery system for quercetin. The encapsulation efficiency, physicochemical stability and release properties of the nanoparticles were estimated. The FTIR and secondary structure analysis indicated that hydrogen bonds, hydrophobic interactions and electrostatic attractions were formed in the quercetin-loaded hordein/pectin nanoparticles (Que-hordein/pectin NPs). In comparison to Que-hordein NPs, Que-hordein/pectin NPs exhibited better colloidal stability (physical, UV light, heating and salt). Furthermore, the release properties studies showed that pectin coating restrained the premature release of Que from hordein NPs in gastric fluid and intestinal fluid. In-vitro release, when the Que-hordein/pectin NPs were exposed to simulated colonic fluid (SCF) for 6 h, quercetin was greatly released from the hordein/pectin NPs (15.29 ± 1.17% - 80.60 ± 1.78%). In-vivo release, the concentration of Que (μg/g) in Que-hordein/pectin NPs was 2.18 times higher than Que-hordein NPs in colon tissue after 6 h of oral administration. This study suggests that Que-hordein/pectin NPs have promising applications in the specific delivery and release of quercetin to the colon.

Encapsulation of tea polyphenols into high amylose corn starch composite nanofibrous film for active antimicrobial packaging

Starch-based composite nanofibrous films loaded with tea polyphenols (TP) were successfully fabricated through electrospinning high amylose corn starch (HACS) with aid of polyvinyl alcohol (PVA), referred as HACS/PVA@TP. With the addition of 15 % TP, HACS/PVA@TP nanofibrous films exhibited enhanced mechanical properties and water vapor barrier capability, and their hydrogen bonding interactions were further evidenced. TP was slowly released from the nanofibrous film and followed Fickian diffusion mechanism, which achieved the controlled sustained release of TP. Interesting, HACS/PVA@TP nanofibrous films effectively improved antimicrobial activities against Staphylococcus aureus (S. aureus) and prolonged the shelf life of strawberry. HACS/PVA@TP nanofibrous films showed superior antibacterial function by by destroying cell wall and cytomembrane, and degrading existing DNA fragments, stimulating excessive intracellular reactive oxygen species (ROS) generation. Our study demonstrated that the functional electrospun Starch-based nanofibrous films with enhanced mechanical properties and superior antimicrobial activities were potential for the application in active food packaging and relative areas.

Targets Involved in the Anti-Cancer Activity of Quercetin in Breast, Colorectal and Liver Neoplasms

Phytochemicals have long been effective partners in the fight against several diseases, including cancer. Among these, flavonoids are valuable allies for both cancer prevention and therapy since they are known to influence a large panel of tumor-related processes. Particularly, it was revealed that quercetin, one of the most common flavonoids, controls apoptosis and inhibits migration and proliferation, events essential for the development of cancer. In this review, we collected the evidence on the anti-cancer activity of quercetin exploring the network of interactions between this flavonol and the proteins responsible for cancer onset and progression focusing on breast, colorectal and liver cancers, owing to their high worldwide incidence. Moreover, quercetin proved to be also a potentiating agent able to push further the anti-cancer activity of common employed anti-neoplastic agents, thus allowing to lower their dosages and, above all, to sensitize again resistant cancer cells. Finally, novel approaches to delivery systems can enhance quercetin's pharmacokinetics, thus boosting its great potentiality even further. Overall, quercetin has a lot of promise, given its multi-target potentiality; thus, more research is strongly encouraged to properly define its pharmaco-toxicological profile and evaluate its potential for usage in adjuvant and chemoprevention therapy.

Dual role of quercetin in enhancing the efficacy of cisplatin in chemotherapy and protection against its side effects: a review

Chemotherapy has opened a new window in cancer therapy. However, the resistance of cancer cells has dramatically reduced the efficacy of chemotherapy. Cisplatin is a chemotherapeutic agent and its potential in cancer therapy has been restricted by resistance of cancer cells. As a consequence, the scientists have attempted to find new strategies in elevating chemotherapy efficacy. Due to great anti-tumour activity, naturally occurring compounds are of interest in polychemotherapy. Quercetin is a flavonoid with high anti-tumour activity against different cancers that can be used with cisplatin to enhance its efficacy and also are seen to sensitise cancer cells into chemotherapy. Furthermore, cisplatin has side effects such as nephrotoxicity and ototoxicity. Administration of quercetin is advantageous in reducing the adverse effects of cisplatin without compromising its anti-tumour activity. In this review, we investigate the dual role of quercetin in enhancing anti-tumour activity of cisplatin and simultaneous reduction in its adverse effects.

Metronidazole Delivery Nanosystem Able To Reduce the Pathogenicity of Bacteria in Colorectal Infection

Metronidazole (MTZ) is a drug potentially used for the treatment of intestinal infections, namely, the ones caused by colorectal surgery. The traditional routes of administration decrease its local effectiveness and present off-site effects. To circumvent such limitations, herein a drug delivery system (DDS) based on MTZ-loaded nanoparticles (NPs) immobilized at the surface of electrospun fibrous meshes is proposed. MTZ at different concentrations (1, 2, 5, and 10 mg mL^-1) was loaded into chitosan-sodium tripolyphosphate NPs. The MTZ loaded into NPs at the highest concentration showed a quick release in the first 12 h, followed by a gradual release. This DDS was not toxic to human colonic cells. When tested against different bacterial strains, a significant reduction of Escherichia coli and Staphylococcus aureus was observed, but no effect was found against Enterococcus faecalis. Therefore, this DDS offers high potential to locally prevent the occurrence of infections after colorectal anastomosis.

Multifunctional mesoporous silica nanoparticles for pH-response and photothermy enhanced osteosarcoma therapy

The recurrence and bone defect of malignant osteosarcoma postsurgical treatment have gained remarkable attention. Therefore, the development of multifunctional treatment platform is urgently desirable to achieve efficient tumor treatment and bone regeneration. In this paper, a multifunctional nanomaterial using mesoporous silica (MSN) as platform modified with quercetin (Qr), collagen (Col) and dopamine (PDA) was developed. Our findings demonstrated that the nanoparticles designed in this work had excellent photothermal properties and pH responsiveness. In addition, the nanoparticles had outstanding anti-tumor ability and could killed Saos-2 cells within 10 min under 808 nm laser irradiation owing to the synergistic effect of hyperthermia and Qr. Besides, the modification of PDA and Col endows the nanoparticles with excellent osteogenic activity.

Drug Delivery Applications of Coaxial Electrospun Nanofibres in Cancer Therapy

Cancer is one of the most serious health problems and the second leading cause of death worldwide, and with an ageing and growing population, problems related to cancer will continue. In the battle against cancer, many therapies and anticancer drugs have been developed. Chemotherapy and relevant drugs are widely used in clinical practice; however, their applications are always accompanied by severe side effects. In recent years, the drug delivery system has been improved by nanotechnology to reduce the adverse effects of the delivered drugs. Among the different candidates, core-sheath nanofibres prepared by coaxial electrospinning are outstanding due to their unique properties, including their large surface area, high encapsulation efficiency, good mechanical property, multidrug loading capacity, and ability to govern drug release kinetics. Therefore, encapsulating drugs in coaxial electrospun nanofibres is a desirable method for controlled and sustained drug release. This review summarises the drug delivery applications of coaxial electrospun nanofibres with different structures and drugs for various cancer treatments.

Electrospun Nanofibers: Current Progress and Applications in Food Systems

Electrospinning has the advantages of simple manufacturing equipment, a low spinning cost, wide range of spinnable materials, and a controllable mild process, which can continuously fabricate submicron or nanoscale ultrafine polymer fibers without high temperature or high pressure. The obtained nanofibrous films may have a large specific surface area, unique pore structure, and easy-to-modify surface characteristics. This review briefly introduces the types and fiber structures of electrospinning and summarizes the applications of electrospinning for food production (e.g., delivery systems for functional food, filtration of beverages), food packaging (e.g., intelligent packaging, antibacterial packaging, antioxidant packaging), and food analysis (e.g., pathogen detection, antibiotic detection, pesticide residue detection, food compositions analysis), focusing on the advantages of electrospinning applications in food systems. Furthermore, the limitations and future research directions of the technique are discussed.

Development of Nervilia fordii Extract-Loaded Electrospun PVA/PVP Nanocomposite for Antioxidant Packaging

An ethyl acetate extract from of Nervilia fordii (NFE) with considerable suppression activity on lipid peroxidation (LPO) was first obtained with total phenolic and flavonoid contents and anti-LPO activity (IC₅₀) of 86.67 ± 2.5 mg GAE/g sample, 334.56 ± 4.7 mg RE/g extract and 0.307 mg/mL, respectively. In order to improve its stability and expand its application in antioxidant packaging, the nano-encapsulation of NFE within poly(vinyl alcohol) (PVA) and polyvinyl(pyrrolidone) (PVP) bio-composite film was then successfully developed using electrospinning. SEM analysis revealed that the NFE-loaded fibers exhibited similar morphology to the neat PVA/PVP fibers with a bead-free and smooth morphology. The encapsulation efficiency of NFE was higher than 90% and the encapsulated NFE still retained its antioxidant capacity. Fourier transform infrared spectroscopy (FTIR) and X-ray powder diffraction (XRD) analysis confirmed the successful encapsulation of NFE into fibers and their compatibility, and the thermal stability of which was also improved due to the intermolecular interaction demonstrated by thermo gravimetric analysis (TGA). The ability to preserve the fish oil’s oxidation and extend its shelf-life was also demonstrated, suggesting the obtained PVA/PVP/NFE fiber mat has the potential as a promising antioxidant food packaging material.

Orally Administrable Therapeutic Nanoparticles for the Treatment of Colorectal Cancer

Colorectal cancer (CRC) is one of the most common and lethal human malignancies worldwide; however, the therapeutic outcomes in the clinic still are unsatisfactory due to the lack of effective and safe therapeutic regimens. Orally administrable and CRC-targetable drug delivery is an attractive approach for CRC therapy as it improves the efficacy by local drug delivery and reduces systemic toxicity. Currently, chemotherapy remains the mainstay modality for CRC therapy; however, most of chemo drugs have low water solubility and are unstable in the gastrointestinal tract (GIT), poor intestinal permeability, and are susceptible to P-glycoprotein (P-gp) efflux, resulting in limited therapeutic outcomes. Orally administrable nanoformulations hold the great potential for improving the bioavailability of poorly permeable and poorly soluble therapeutics, but there are still limitations associated with these regimes. This review focuses on the barriers for oral drug delivery and various oral therapeutic nanoparticles for the management of CRC.

Application of quercetin flavonoid based hybrid nanocomposites: A review

Natural bioflavonoids are an essential component of dietary supplements possessing antimicrobial properties. Many of the bioflavonoids have resulted in positive antitumor, anticancer, antibacterial, antifungal, anti-inflammatory properties, but the efficacy remains low due to toxicity at the molecular level whereas antiviral property limits to negative. The synergistic link between nanoscience and flavonoid chemistry enhances the epidemiological properties of flavonoid and also diminish the antimicrobial resistivity (AMR) by forming their hybrid nanocomposites. Nanochemistry uses various nanocomposite and nanomaterials for biosensing the flavonoids and their delivery as a drug. The quercetin flavonoid and its derivatives such as rutin, and myricetin are used for sensing and drug delivery. Quercetin with 15Carbon-5Hydroxyl chemical scaffold has been explored for a few decades for the development of hybrid nanocomposite and nanomaterial with metallic as well as organic nano co-composites. This quercetin flavonoid based hybrid nanocomposites seemed to show a significant effect on In vitro and some animal model processes along with attenuating lipid peroxidation, platelet aggregation, and capillary permeability actions. This review mainly focused on the hybrid nanoscience of quercetin bioflavonoid and its application in numerous biological, material fields with a future perspective.

Bridging the Gap of Drug Delivery in Colon Cancer: The Role of Chitosan and Pectin Based Nanocarriers System

Colon cancer is one of the most prevalent diseases, and traditional chemotherapy has not been proven beneficial in its treatment. It ranks second in terms of mortality due to all cancers for all ages. Lack of selectivity and poor biodistribution are the biggest challenges in developing potential therapeutic agents for the treatment of colon cancer. Nanoparticles hold enormous prospects as an effective drug delivery system. The delivery systems employing the use of polymers, such as chitosan and pectin as carrier molecules, ensure the maximum absorption of the drug, reduce unwanted side effects and also offer protection to the therapeutic agent from quick clearance or degradation, thus allowing an increased amount of the drug to reach the target tissue or cells. In this systematic review of published literature, the author aimed to assess the role of chitosan and pectin as polymer-carriers in colon targeted delivery of drugs in colon cancer therapy. This review summarizes the various studies employing the use of chitosan and pectin in colon targeted drug delivery systems.

Core-Shell Fibers: Design, Roles, and Controllable Release Strategies in Tissue Engineering and Drug Delivery

The key attributes of core-shell fibers are their ability to preserve bioactivity of incorporated-sensitive biomolecules (such as drug, protein, and growth factor) and subsequently control biomolecule release to the targeted microenvironments to achieve therapeutic effects. Such qualities are highly favorable for tissue engineering and drug delivery, and these features are not able to be offered by monolithic fibers. In this review, we begin with an overview on design requirement of core-shell fibers, followed by the summary of recent preparation methods of core-shell fibers, with focus on electrospinning-based techniques and other newly discovered fabrication approaches. We then highlight the importance and roles of core-shell fibers in tissue engineering and drug delivery, accompanied by thorough discussion on controllable release strategies of the incorporated bioactive molecules from the fibers. Ultimately, we touch on core-shell fibers-related challenges and offer perspectives on their future direction towards clinical applications.

Electrospun Nanofibers for Drug Delivery and Biosensing

Early diagnosis and efficient treatment are of paramount importance to fighting cancers. Monitoring the foreign body response of a patient to treatment therapies also plays an important role in improving the care that cancer patients receive by their medical practitioners. As such, there is extensive research being conducted into ultrasensitive point-of-care detection systems and "smart" personalized anticancer drug delivery systems. Electrospun nanofibers have emerged as promising materials for the construction of nanoscale biosensors and therapeutic platforms because of their large surface areas, controllable surface conformation, good surface modification, complex pore structure, and high biocompatibility. Electrospun nanofibers are produced by electrospinning, which is a very powerful and economically viable method of synthesizing versatile and scalable assemblies from a wide array of raw materials. This review describes the theory of electrospinning, achievements, and problems currently faced in producing effective biosensors/drug delivery systems, in particular, for cancer diagnosis and treatment. Finally, insights into future prospects are discussed.

Targeted delivery of phycocyanin for the prevention of colon cancer using electrospun fibers

Phycocyanin (PC), a water-soluble biliprotein, exhibits potent anti-colon cancer properties. However, its application in functional foods is limited by the poor stability and low bioavailability of PC. In this study, we successfully encapsulated PC by coaxial electrospinning. The colon targeted release of PC was achieved with retention of the antioxidant activity of PC. The PC-loaded electrospun fiber mat (EFM) obtained inhibited HCT116 cell growth in a dose-dependent and time-dependent manner. In particular, the PC-loaded EFM exerted its anti-cancer activity by blocking the cell cycle at the G0/G1 phase and inducing cell apoptosis involving the decrease of Bcl-2/Bax, activation of caspase 3 and release of cytochrome c. This study suggests that co-axial electrospinning is an efficient and effective way to deliver PC and improve its bioavailability; thus, it represents a promising approach for encapsulating functional ingredients for colon cancer prevention.

A colon-specific delivery system for quercetin with enhanced cancer prevention based on co-axial electrospinning

The antioxidant quercetin (Q) is a bioactive compound that can inhibit colon cancer. However, its poor stability in the upper gastro-intestinal tract and low bioavailability compromised its benefits. In this study, a biopolymer-based colon-specific delivery system for Q was constructed by co-axial electrospinning. Quercetin-loaded chitosan nanoparticles (QCNP) were firstly prepared and characterized. Then, a Q-loaded electrospun fiber mat (Q-loaded EFM) containing prebiotics (galactooligosaccharide, GOS) was fabricated using sodium alginate as the shell layer and the abovementioned QCNP and prebiotics as the core layer. The DPPH assay showed that the antioxidant activity of Q was maintained in the obtained film. Owing to the addition of prebiotic GOS, the obtained fiber mat exhibited good prebiotic effects. In vitro release kinetics showed a sustained and targeted colon-specific release of Q from the Q-loaded EFM containing GOS, and the release rate of Q was enhanced by the presence of GOS. The obtained film also exhibited inhibition effects on Caco-2 cells in a dose- and time-dependent manner. Flow cytometry and fluorescence microscopy analysis indicated that the Q-loaded EFM containing GOS exerted its activity on colonic cancer cells by arresting the cell cycle in the G0/G1 phase and triggering apoptotic cell death. This study demonstrates the potential of the obtained film as an oral delivery system for encapsulation, protection, and release of Q at the colon for the oral therapy of colon disorders.