Polycaprolactone/chitosan blend nanofibers loaded by 5-fluorouracil: An approach to anticancer drug delivery system

DFT investigation of 5-fluorouracil tautomerism and non-covalent interactions with PLGA nanoparticles for enhanced drug delivery and sensing

This study investigates the non-covalent interactions between both the free and tautomeric forms of 5-fluorouracil (5-FU) and poly(lactic-co-glycolic acid) (PLGA) nanoparticles through density functional dispersion correction (DFT-D) at the B3LYP-D level in a dichloromethane (DCM) and water environments. Our results indicate that the non-covalent interactions formed between the carbonyl and amide groups of the free form of 5-FU and the carboxyl group of PLGA facilitate a rapid initial release of the drug, aligning with experimental findings. The calculated binding energies for 5-FU in its keto-enol (-0.80 eV) and di-enol forms (-0.74 eV) demonstrate exothermic processes, highlighting the enhanced drug loading capacity of the tautomeric forms compared to the free form (-0.627 eV). NBO analysis indicates a charge transfer of 0.061e in the keto-enol form, compared to 0.053e in the free form. Infrared (IR) spectra show shifts in the N-H and CO stretching frequencies, suggesting the formation of hydrogen bonds between 5-FU and the carbonyl groups of PLGA. Time-dependent DFT calculations revealed significant shifts in the optical properties of 5-FU upon interaction with the PLGA carrier. Adsorption of 5-FU in its most stable configuration resulted in a red shift to 253.56 nm, while the PLGA carrier exhibited a blue shift to 213.08 nm. Analysis of oscillator strengths indicated an increased adsorption intensity for the keto-enol form of 5-FU, suggesting a hypochromic effect. Total density of states (TDOS) analysis demonstrates that 5-FU notably influences the HOMO and LUMO levels, with PLGA nanoparticles exhibiting higher sensitivity (state I: 30.07 %) to 5-FU in one state compared to another (state VII: 28.99 %), likely due to variations in energy gaps. These findings indicate that PLGA nanoparticles possess significant potential as both drug carriers and sensors for 5-FU detection in solvent phases.

Polyethylene oxide-chitosan-doxorubicin/polycaprolactone-chitosan-curcumin pH-sensitive core/shell nanofibrous mats for the treatment of breast cancer: Fabrication, characterization and in vitro and in vivo evaluation

The main objective of this study was to fabricate a pH-sensitive drug carrier based on coaxial electrospun nanofibrous mats for concurrent local delivery of hydrophilic and hydrophobic anti-cancer drugs to improve the anti-tumor efficacy on breast cancer. Therefore, co-axial electrospinning technique was applied to prepare polyethylene oxide-chitosan/polycaprolactone-chitosan (PEO-CS/PCL-CS) pH-sensitive core-shell nanofibers. Doxorubicin hydrochloride (DOX, hydrophilic anti-cancer) and curcumin (CUR, hydrophobic anticancer) were loaded into core and shell sections of the fabricated pH-sensitive coaxial nanofibers, respectively. Their structure and morphology were analyzed via SEM, TEM, TGA, and FTIR techniques. The results of in vitro release analysis indicated that the release of DOX and CUR from the fabricated nanofibers was strongly depended on pH. The combined effects of the two drugs on MCF-7 cell inhibition, as measured by the MTT assay, revealed that the 1:5 ratio of DOX to CUR resulted in a CI of 0.00492, showing the strongest synergistic effect. The results of in-vivo studies indicated that the PEO-CS-DOX/PCL-CS-CUR pH-sensitive core-shell nanofibers possessed remarkable anti-tumor efficacy. As a result, PEO-CS-DOX/PCL-CS-CUR pH-sensitive core-shell nanofibrous mats with pH-responsive and sustainable and controllable manner could improve the local anti-tumor efficacy on breast cancer via inhibiting the side effects of free DOX and CUR drugs.

Gelatin Multiwalled Carbon Nanotube Composite 3D Printed Semi Biological Mesh for Abdominal Hernia Treatment

Hernia is characterized by the protrusion of organs or tissue through weakened areas in the abdominal cavity wall. A common treatment for hernia involves the implantation of a mesh which promotes the growth of new tissue around or within the implanted material in the damaged area. The mesh is typically made from synthetic materials like polypropylene. However, such meshes have safety concerns like biofilm and scar tissue formation, foreign body reactions, and chronic pain. These concerns gave rise to the development of biological meshes. Owing to mechanical weakness, biological meshes fail due to migration and rapid degradation. This study is aimed to develop a mechanically viable biopolymer-based composite degradable mesh. A gelatin-MWCNT composite 3D printed mesh has been developed with different pore sizes and filament sizes. Adding MWCNTs improved the composite's ductility, printability, hydrophilicity, and modulus, and reduced its degradation rate. The 3D-printed mesh also showed signs of cell attachment and proliferation representing non-toxicity of MWCNTs within the composite materials. The data showed improved cell adherence due to the incorporation of MWCNTs within the composite materials. Among the various material compositions tested, the composite material with gelatin with 0.01 g MWCNTs gave the optimum mechanical strength and biocompatibility results.

Designing sustained release from nanofiber patch for paclitaxel as prospective localized nanotherapeutic delivery in breast cancer

The second most prevalent cause of mortality among women is breast cancer, and paclitaxel (PTX) is an effective drug for its treatment. The present work aims to develop patch-based poly(ε-caprolactone) (PCL) nanofibers incorporating PTX as a localized and sustained drug delivery system. The co-deposition of poly(vinyl alcohol) (PVA) fibers during electrospinning was allowed to improve water absorption by the scaffold, which in turn facilitated the release of drug molecules. To figure out optimized electrospinning parameters and predict the optimal formulation, the quality-by-design approach was utilized. The blank mat, i.e., without drug and optimized nanofiber formulation (Fo), was characterized physiochemically using FE-SEM, XRD, FT-IR, TGA and DSC techniques. The optimization yielded a 92.7 % final product yield, indicating high process efficiency and minimum losses during electrospinning. FE-SEM studies have demonstrated that uniform nanofibers with bead-free morphology. The average fiber diameter and drug entrapment of the optimal formulation, Fo, were 547 ± 6.6 nm and 85 ± 1.73 %, respectively. Diffraction and calorimetric studies revealed a sharp decrease in the crystallinity of pure PTX and its subsequent amorphization within the nanofiber matrix. FT-IR studies showed no chemical interaction between the drug and polymers. A decrease in water contact angle from 120.4 ± 0.9 to 81.0 ± 0.8 in the Fo formulation was due to the co-spinning of PVA; this ensures proper wettability and adhesion ideal for localized delivery. The Fo nanofiber formulation demonstrated sustained PTX release for up to 17 days. The MTT assay results confirm Fo nanofibers were cytotoxic to the breast cancer cell line, MDA-MB-231, than pristine nanofibers. These findings suggest that Fo nanofiber mats could be a potential localized delivery system for PTX in breast cancer treatment, pending further in-vivo validation.

Fiber Technology in Drug Delivery and Pharmaceuticals

The field of fiber technology is a dynamic and innovative domain that offers novel solutions for controlled and targeted therapeutic interventions. This abstract provides an overview of key aspects within this field, encompassing a range of techniques, applications, commercial developments, intellectual property, and regulatory considerations. The foundational introduction establishes the significance of fiber-based drug delivery systems. Electrospinning, a pivotal technique, has been explored in this paper, along with its various methods and applications. Monoaxial, coaxial, triaxial, and side-by-side electrospinning techniques each offer distinct advantages and applications. Centrifugal spinning, solution and melt blowing spinning, and pressurized gyration further contribute to the field's diversity. The review also delves into commercial advancements, highlighting marketed products that have successfully harnessed fiber technology. The role of intellectual property is acknowledged, with patents reflecting the innovative strides in fiber-based drug delivery. The regulatory perspective, essential for ensuring safety and efficacy, is discussed in the context of global regulatory agencies' evaluations. This review encapsulates the multidimensional nature of fiber technology in drug delivery and pharmaceuticals, showcasing its potential to revolutionize medical treatments and underscores the importance of continued collaboration between researchers, industry, and regulators for its advancement.

Advanced applications of smart electrospun nanofibers in cancer therapy: With insight into material capabilities and electrospinning parameters

Cancer remains a major global health challenge, and despite available treatments, its prognosis remains poor. Recently, researchers have turned their attention to intelligent nanofibers for cancer drug delivery. These nanofibers exhibit remarkable capabilities in targeted and controlled drug release. Their inherent characteristics, such as a high surface area-to-volume ratio, make them attractive candidates for drug delivery applications. Smart nanofibers can release drugs in response to specific stimuli, including pH, temperature, magnetic fields, and light. This unique feature not only reduces side effects but also enhances the overall efficiency of drug delivery systems. Electrospinning, a widely used method, allows the precision fabrication of smart nanofibers. Its advantages include high efficiency, user-friendliness, and the ability to control various manufacturing parameters. In this review, we explore the latest developments in producing smart electrospun nanofibers for cancer treatment. Additionally, we discuss the materials used in manufacturing these nanofibers and the critical parameters involved in the electrospinning process.

Stability, challenges, and prospects of chitosan for the delivery of anticancer drugs and tissue regenerative growth factors

Chitosan, a biopolymer derived from chitin, offers significant potential for regulated anticancer drug administration and tissue regeneration growth factors, owing to its biocompatibility, low toxicity, biodegradability, and little immunogenicity. Moreover, its structure can be extensively modified, for example, to create scaffolds, hydrogels, nanoparticles, and membranes, allowing it to be engineered precisely to achieve specific outcomes However, the therapeutic utilisation of chitosan is impeded by significant challenges, such as its inadequate hemocompatibility, durability, and uniformity in commercial manufacturing. Additionally, there is insufficient research offering a thorough examination of the capabilities, limitations, and challenges related to chitosan as carriers for anticancer drugs and growth factors. This article examines the stability, challenges, and advanced application of chitosan as a drug carrier in anti-cancer therapy and growth factor delivery. The problems of unregulated chitosan degradation arising from unsuitable storage conditions are considered and potential solutions, and areas for future research, are proposed to deal with such problems. Consequently, this review is expected to be highly valuable for aspiring scientists studying chitosan-related systems for delivery of anti-cancer drugs and growth factors.

Fabrication and Evaluation of a Soy Protein Isolate/Collagen/Sodium Alginate Multifunctional Bilayered Wound Dressing: Release of Cinnamaldehyde, Artemisia absinthium, and Oxygen

Chronic wounds, such as diabetic ulcers and pressure sores, pose significant challenges in modern healthcare due to their prolonged healing times and susceptibility to infections. This study aims to engineer a bilayered wound dressing (BLWD) composed of soy protein isolate/collagen with the ability to release Cinnamaldehyde, Artemisia absinthium (AA), and oxygen. Cinnamaldehyde, magnesium peroxide (MgO2), and AA extract were encapsulated. Nanoparticles were evaluated using scanning electron microscopy (SEM), dynamic light scattering, and ZETA potential tests. Swelling, degradation, water vapor penetration, tensile, MTT, SEM, oxygen release, AA extract release, and antibacterial properties were performed. An in vivo study was carried out to assess the final wound dressing under Hematoxiline&Eosin and Masson trichrome staining analysis and compared to a commercial product. According to the results, the synthesized nanoparticles had an average diameter of about 20 nm with a zeta potential in the range of -20 to -30 mV. The layers had uniform and dense surfaces. The maximum swelling and degradation of the dressing was about 130 and 13% respectively. Generally, better mechanical properties were observed in BLWD than in the single-layer case. More than 90% biocompatibility for the wound dressing was reported. The BLWD could inhibit the growth of Gram-positive and Gram-negative microorganisms. Histopathological analysis showed an acceptable wound-healing property. To sum up, the engineered wound dressing can be a good candidate for more clinical trials.

A doxycycline-loaded microfiber of poly-metformin/PCL for eradicating melanoma stem cells

Nowadays, electrospun fibrous mats are used as drug delivery systems for loading of potential drugs in order to kill cancer cells. In the study, a skin patch for treating melanoma cancer after surgery was made using polycaprolactone and polymetformin microfibers that were loaded with doxycycline (PolyMet/PCL@DOX), an anti-cancer stem cell agent. The morphology, structure, mechanical characteristics, swelling, and porosity of the electrospun microfibers were examined. Drug release andanticancereffectiveness of PolyMet/PCL@DOXwas evaluated against A375 melanoma cancer stem cells using the MTS, Flow cytometry, colony formation and CD44 expression assays. Scanning electron microscopy (SEM) verified the micro fibrous structure with a diameter of about 2.31 µm. The porosity and swelling percentages for microfibers was 73.5 % and 2.9 %, respectively. The tensile strength at the breaking point was equal to 3.84 MPa. The IC50 of PolyMet/PCL@DOX was 7.4 μg/mL. The survival rate of A375 cells after 72 h of PolyMet/PCL@DOX treatment was 43.9 %. The colony formation capacity of A375 cells decreased after PolyMet/PCL@DOX treatment. The level of CD44 expression in the PolyMet/PCL@DOX group decreased compared to the control group. Generally, PolyMet/PCL@DOX microfibers can be a promising candidate as a patch after surgery to eradicate cancer stem cells, effectively.

Chrysin loaded polycaprolactone-chitosan electrospun nanofibers as potential antimicrobial wound dressing

In this study, various concentrations of chrysin (chry) were loaded into polycaprolactone-chitosan (PCL-CTS) nanofibers to develop a potential wound dressing materials using electrospinning method. The structural composition and the morphology of the produced PCL-CTS5, PCL-CTS10 and PCL-CTS15 were analyzed by FE-SEM and FTIR, respectively. By increasing the amount of chry, the average diameter of the nanofibres was also increased to 191 ± 65 nm, 203 ± 72 nm, and 313 ± 69 nm for PCL-CTS5, PCL-CTS10, and PCL-CTS15, respectively. Moreover, the physicochemical characteristics and biological properties of synthesized nanofibers such as tensile testing, in-vitro drug release, porosity, decomposition rate, water absorption rate, water vapor permeability rate, cell viability, antioxidant and antibacterial activity were evaluated. By using Korsmeyer-Peppas and Higuchi kinetic models, the chry release mechanism in all nanofibers was studied in PBS solution, which suggested a Fick's diffusion. In-vitro antioxidant experiments by DPPH assay indicated 24, 43, 61 and 78 % free radical scavenging activity for PCL-CTS, PCL-CTS5, PCL-CTS10 and PCL-CTS15. In-vitro antibacterial examination showed that chry-loaded nanofibers had high antibacterial activity in which were comparable with the standard reagents. In-vitro cytotoxicity results obtained by MTT assay indicated a desired cytocompatibility towards fibroblast cells.

Composite Hydrogel of Poly(vinyl alcohol) Loaded by Citrus hystrix Leaf Extract, Chitosan, and Sodium Alginate with In Vitro Antibacterial and Release Test

Citrus hystrix leaves have been used traditionally as a spice, a traditional medicine for respiratory and digestive disorders, and a remedy for bacterial infections. This study reports on the synthesis of composite hydrogels using the freeze-thaw method with poly(vinyl alcohol) (PVA) as the building block loaded by C. hystrix leaf extract (CHLE). Additionally, chitosan (CS) and sodium alginate (SA) were also loaded, respectively, to increase the antibacterial activity and to control the extract release of the composite hydrogels. The combinations of the compositions were PVA, PVA/CHLE, PVA/CHLE/CS, PVA/CHLE/SA, and PVA/CHLE/SA/CS. The internal morphology of the hydrogels shows some changes after the PVA/CHLE hydrogel was loaded by CS, SA, and SA/CS. The analysis of the Fourier transform infrared (FTIR) spectra confirmed the presence of PVA, CHLE, CS, and SA in the composite hydrogels. From the X-ray diffraction (XRD) characterization, it was shown that the composite hydrogels maintained their semicrystalline properties with decreasing crystallinity degree after being loaded by CS, SA, and SA/CS, as also supported by differential scanning calorimetry (DSC) characterization. The compressive strength of the PVA/CHLE hydrogel decreases after the loading of CS, SA, and SA/CS, so that it becomes more elastic. Despite being loaded in the composite hydrogels, the CHLE retained its antibacterial activity, as evidenced in the in vitro antibacterial test. The loading of CS succeeded in increasing the antibacterial activity of the composite hydrogels, while the loading of SA resulted in the decrease of the antibacterial activity. The release of extract from the composite hydrogels was successfully slowed down after the loading of CS, SA, and SA/CS, resulting in a controlled release following the pseudo-Fickian diffusion. The cytotoxic activity test proved that all hydrogel samples can be used safely on normal cells up to concentrations above 1000 μg/mL.

Synergistic anticancer effect of Pistacia lentiscus essential oils and 5-Fluorouracil co-loaded onto biodegradable nanofibers against melanoma and breast cancer

Chemoresistance and severe toxicities represent major drawbacks of chemotherapy. Natural extracts, including the essential oils of Pistacia lentiscus (PLEO), exhibit substantial anticancer and anti-inflammatory activities where different cancers are reported to dramatically recess following targeting with PLEO. PLEO has promising antimicrobial, anticancer, and anti-inflammatory properties. However, the therapeutic properties of PLEO are restricted by limited stability, bioavailability, and targeting ability. PLEO nanoformulation can maximize their physicochemical and therapeutic properties, overcoming their shortcomings. Hence, PLEO was extracted and its chemical composition was determined by GC-MS. PLEO and 5-Fluorouracil (5FU) were electrospun into poly-ε-caprolactone nanofibers (PCL-NFs), of 290.71 nm to 680.95 nm diameter, to investigate their anticancer and potential synergistic activities against triple-negative breast cancer cells (MDA-MB-231), human adenocarcinoma breast cancer cells (MCF-7), and human skin melanoma cell line (A375). The prepared nanofibers (NFs) showed enhanced thermal stability and remarkable physical integrity and tensile strength. Biodegradability studies showed prolonged stability over 42 days, supporting the NFs use as a localized therapy of breast tissues (postmastectomy) or melanoma. Release studies revealed sustainable release behaviors over 168 h, with higher released amounts of 5FU and PLEO at pH 5.4, indicating higher targeting abilities towards cancer tissues. NFs loaded with PLEO showed strong antioxidant properties. Finally, NFs loaded with either PLEO or 5FU depicted greater anticancer activities compared to free compounds. The highest anticancer activities were observed with NFs co-loaded with PLEO and 5FU. The developed 5FU-PLEO-PCL-NFs hold potential as a local treatment of breast cancer tissues (post-mastectomy) and melanoma to minimize their  possible recurrence.

Electrospun PVA Fibers for Drug Delivery: A Review

Innovation in biomedical science is always a field of interest for researchers. Drug delivery, being one of the key areas of biomedical science, has gained considerable significance. The utilization of simple yet effective techniques such as electrospinning has undergone significant development in the field of drug delivery. Various polymers such as PEG (polyethylene glycol), PLGA (Poly(lactic-co-glycolic acid)), PLA(Polylactic acid), and PCA (poly(methacrylate citric acid)) have been utilized to prepare electrospinning-based drug delivery systems (DDSs). Polyvinyl alcohol (PVA) has recently gained attention because of its biocompatibility, biodegradability, non-toxicity, and ideal mechanical properties as these are the key factors in developing DDSs. Moreover, it has shown promising results in developing DDSs individually and when combined with natural and synthetic polymers such as chitosan and polycaprolactone (PCL). Considering the outstanding properties of PVA, the aim of this review paper was therefore to summarize these recent advances by highlighting the potential of electrospun PVA for drug delivery systems.

Polyurethane-based nanofibrous mat containing porphyrin with photosensitivity and bactericidal properties can promote cutaneous tissue healing in rats

The regeneration of cutaneous tissue is one of the most challenging issues in human regenerative medicine. To date, several studies have been done to promote cutaneous tissue healing with minimum side effects. The healing potential of polyurethane (PU)/Poly (caprolactone)-poly (ethylene glycol)-poly (caprolactone) (PCEC)/chitosan (CS) (PCS) nanofibrous mat with cationic photosensitizer meso tetrakis (N-methyl pyridinium-4-yl) porphyrin tetratosylate salt (TMP) was examined. The CS tripolyphosphate nanoparticles (CSNPs) were prepared and loaded by TMP to provide an efficient drug release system (TMPNPs) for delivery of TMP to promote wound healing. In in vitro setting, parameters such as bactericidal effects, cytocompatibility, and hemolytic effects were examined. The healing potential of prepared nanofibrous mats was investigated in a rat model of full-thickness cutaneous injury. PCS/TMP/TMPNPs nanofibers can efficiently release porphyrin in the aqueous phase. The addition of TMPNPs and CS to the PU backbone increased the hydrophilicity, degradation, and reduced mechanical properties. The culture of human fetal foreskin fibroblasts (HFFF2) on PCS/TMP/TMPNPs scaffold led to an increased survival rate and morphological adaptation analyzed by MTT and SEM images. Irradiation with a red laser (635 nm, 3 J/cm2) for the 30 s reduced viability of S. aureus and E. Coli bacteria plated on PCS/TMP and PCS/TMP/TMPNPs nanofibrous mats compared to PU/PCEC (PC) and PU/PCEC/CS (PCS) groups, indicating prominent antibacterial effects of PCS/TMP and PCS/TMP/TMPNPs nanofibrous (p < 0.05). Data indicated that PCS/TMP/TMPNPs mat enhanced healing of the full-thickness excisional wound in a rat model by the reduction of inflammatory response and fibrotic changes compared to the PC, and PCS groups (p < 0.05). Immunofluorescence imaging indicated that levels of Desmoglein were increased in rats that received PCS/TMP/TMPNPs compared to the other groups. It is found that a PU-based nanofibrous mat is an appropriate scaffold to accelerate the healing of injured skin.

Controlled Drug Release from Nanoengineered Polysaccharides

Polysaccharides are naturally occurring complex molecules with exceptional physicochemical properties and bioactivities. They originate from plant, animal, and microbial-based resources and processes and can be chemically modified. The biocompatibility and biodegradability of polysaccharides enable their increased use in nanoscale synthesis and engineering for drug encapsulation and release. This review focuses on sustained drug release studies from nanoscale polysaccharides in the fields of nanotechnology and biomedical sciences. Particular emphasis is placed on drug release kinetics and relevant mathematical models. An effective release model can be used to envision the behavior of specific nanoscale polysaccharide matrices and reduce impending experimental trial and error, saving time and resources. A robust model can also assist in translating from in vitro to in vivo experiments. The main aim of this review is to demonstrate that any study that establishes sustained release from nanoscale polysaccharide matrices should be accompanied by a detailed analysis of drug release kinetics by modeling since sustained release from polysaccharides not only involves diffusion and degradation but also surface erosion, complicated swelling dynamics, crosslinking, and drug-polymer interactions. As such, in the first part, we discuss the classification and role of polysaccharides in various applications and later elaborate on the specific pharmaceutical processes of polysaccharides in ionic gelling, stabilization, cross-linking, grafting, and encapsulation of drugs. We also document several drug release models applied to nanoscale hydrogels, nanofibers, and nanoparticles of polysaccharides and conclude that, at times, more than one model can accurately describe the sustained release profiles, indicating the existence of release mechanisms running in parallel. Finally, we conclude with the future opportunities and advanced applications of nanoengineered polysaccharides and their theranostic aptitudes for future clinical applications.

Barrier behaviour of partially N-acetylated chitosan layers in aqueous media

Chitosan coatings of 353 ± 12 nm thickness were prepared on glass and zinc substrates by dip-coating method to study their barrier-behaviour. The coatings were chemically modified to increase their degree of acetylation (DA) from ca. 44 % up to ca. 98 % resulting a quasi-chitin coating. The effect of the acetylation reaction was studied by infrared spectroscopy, and the structural changes of the native and acetylated coatings were investigated by UV-Vis spectrophotometry and X-ray diffraction. The surface properties of the coated samples were characterized by wettability measurements - advancing water contact angle decreased from ca. 80° (native) to ca. 43° (fully acetylated) - and microscopic (SEM, AFM) studies. The barrier behaviour of the chitosan layer depending on the DA was evaluated by electrochemical impedance spectroscopy studies and with a special mesoporous silica - chitosan bilayer system by measuring the amount of dye (Rhodamine 6G) accumulated in the silica through the chitosan coating during an impregnation step. These methods showed significant decrease in the barrier-effect of the coatings with increasing DA (accumulation of approximately six times more dye and a reduction of charge transfer resistance by an order of magnitude), due to the structural and ionization changes in the coatings.

Paclitaxel-loaded liposome-incorporated chitosan (core)/poly(ε-caprolactone)/chitosan (shell) nanofibers for the treatment of breast cancer

Liposomes and nanofibers have been introduced as effective drug delivery systems of anticancer drugs. The performance of chitosan (core)/poly(ε-caprolactone) (PCL)/paclitaxel simple nanofibers, chitosan/paclitaxel (core)/PCL/chitosan (shell) nanofibers and paclitaxel-loaded liposome-incorporated chitosan (core)/PCL-chitosan (shell) nanofibers was investigated for the controlled release of paclitaxel and the treatment of breast cancer. The synthesized formulations were characterized using polydispersity index, dynamic light scattering, zeta potential, scanning electron microscopy, transmission electron microscopy, and Fourier transform infrared analysis. The sustained release of paclitaxel from liposome-loaded nanofibers was achieved within 30 days. The release data was best described using Korsmeyer-Peppas pharmacokinetic model. The cell viabilities of synthesized nanofibrous samples were higher than 98 % ± 1 % toward L929 normal cells after 168 h. The maximum cytotoxicity against MCF-7 breast cancer cells was 85 % ± 2.5 % using liposome-loaded core-shell nanofibers. The in vivo results indicated the reduction of tumor weight from 1.35 ± 0.15 g to 0.65 ± 0.05 g using liposome-loaded core-shell nanofibers and its increasing from 1.35 ± 0.15 g to 3.2 ± 0.2 g using pure core-shell nanofibers. The three-stage drug release behavior of paclitaxel-loaded liposome-incorporated core-shell nanofibers and the high in vivo tumor efficiency suggested the development of these formulations for cancer treatment in the future.

Recent Advances in Designing Fibrous Biomaterials for the Domain of Biomedical, Clinical, and Environmental Applications

Unique properties and potential applications of nanofibers have emerged as innovative approaches and opportunities in the biomedical, healthcare, environmental, and biosensor fields. Electrospinning and centrifugal spinning strategies have gained considerable attention among all kinds of strategies to produce nanofibers. These techniques produce nanofibers with high porosity and surface area, adequate pore architecture, and diverse chemical compositions. The extraordinary characteristics of nanofibers have unveiled new gates in nanomedicine to establish innovative fiber-based formulations for biomedical use, healthcare, and a wide range of other applications. The present review aims to provide a comprehensive overview of nanofibers and their broad range of applications, including drug delivery, biomedical scaffolds, tissue/bone-tissue engineering, dental applications, and environmental remediation in a single place. The review begins with a brief introduction followed by potential applications of nanofibers. Finally, the future perspectives and current challenges of nanofibers are demonstrated. This review will help researchers to engineer more efficient multifunctional nanofibers with improved characteristics for their effective use in broad areas. We strongly believe this review is a reader's delight and will help in dealing with the fundamental principles and applications of nanofiber-based scaffolds. This review will assist students and a broad range of scientific communities to understand the significance of nanofibers in several domains of nanotechnology, nanomedicine, biotechnology, and environmental remediation, which will set a benchmark for further research.

Drug-loaded PCL electrospun nanofibers as anti-pancreatic cancer drug delivery systems

Cancer is one of the main causes of death worldwide, being pancreatic cancer the second deadliest cancer in Western countries. Surgery, chemotherapy and radiotherapy form the basis of pancreatic cancer’s current treatment. However, these techniques have several disadvantages, such as surgery complications, chemotherapy systemic side effects and cancer recurrence. Drug delivery systems can reduce side effects, increasing the effectivity of the treatment by a controlled release at the targeted tumor cells. In this context, coaxial electrospun fibers can increase the control on the release profile of the drug. The aim of this study was to encapsulate and release different anticancer drugs (5-Fluorouracil and Methotrexate) from a polymeric fiber mat. Different flows and ratios were used to test their effect on fiber morphology, FTIR spectrum, drug encapsulation and release. Good integration of the anticancer drugs was observed and the use of a desiccator for 24 h showed to be a key step to remove solvent remanence. Moreover, the results of this study demonstrated that the polymeric solution could be used to encapsulate and release different drugs to treat cancers. This makes coaxial electrospinning a promising alternative to deliver complex chemotherapies that involve more than one drug, such as FOLFIRINOX, used in pancreatic cancer treatment.

Medical applications of biopolymer nanofibers

A wide array of biomedical applications, extending from the fabrication of implant materials to targeted drug delivery, can be attributed to polymers. The utilization of chemical monomers to form polymers, such as polypropylene, polystyrene, and polyethylene, can provide high mechanical stability to them and they can be utilized for diverse electronic or thermal applications. However, certain chemical-based synthetic polymers are toxic to humans, animals, plants, and microbial cells. Thus, biopolymers have been introduced as an alternative to make them utilizable for biomedical applications. Even though biopolymers possess beneficial biomedical applications, they are not stable in biological fluids and exhibit toxicity in certain cases. Recent advances in nanotechnology have expanded its applicational significance in various domains, especially in the evolution of biopolymers to transform them into nanoparticles for numerous biomedical applications. In particular, biopolymers are fabricated as nanofibers to enhance their biological properties and to be utilized for exclusive biomedical applications. The aim of this review is to present an overview of various biopolymer nanofibers and their distinct synthesis approaches. In addition, the medical applications of biopolymer nanofibers, including antimicrobial agents, drug delivery systems, biosensor production, tissue engineering, and implant fabrication, are also discussed.

Control of drug release from cotton fabric by nanofibrous mat

A drug delivery system (DDSs) was developed in the present study based on textile substrates as drug carriers and electrospun nanofibers as a controller of release rate. Three types of drugs consisting of ciprofloxacin (CIP), clotrimazole (CLO), and benzalkonium chloride (BEN) were loaded into the cover glass (CG) and cotton fabrics (CF1 and CF2) separately. Then, the drug-loaded substrates were coated with polycaprolactone (PCL) and polycaprolactone/gelatin (PCL/Gel) nanofibers with various thicknesses. The morphology and hydrophilicity of the electrospun nanofibers and the release profile of drug-loaded samples were investigated. FTIR, XRD, and in vitro biodegradability analysis were analyzed to characterize the drug delivery system. A morphological study of electrospun fibers showed the mean diameter of the PCL and PCL/Gel nanofibers 127 ± 25 and 178 ± 38 nm, respectively. The drug delivery assay revealed that various factors affect the rate of drug releases, such as the type of drug, the type of drug carrier, and the thickness of the covered nanofibers. The study highlights the ability of drugs to load substrates with coated nanofibers as controlled drug delivery systems. In conclusion, it is shown that the obtained samples are excellent candidates for future wound dressing applications.

Marine Biopolymers as Bioactive Functional Ingredients of Electrospun Nanofibrous Scaffolds for Biomedical Applications

Marine biopolymers, abundantly present in seaweeds and marine animals, feature diverse structures and functionalities, and possess a wide range of beneficial biological activities. Characterized by high biocompatibility and biodegradability, as well as unique physicochemical properties, marine biopolymers are attracting a constantly increasing interest for the development of advanced systems for applications in the biomedical field. The development of electrospinning offers an innovative technological platform for the production of nonwoven nanofibrous scaffolds with increased surface area, high encapsulation efficacy, intrinsic interconnectivity, and structural analogy to the natural extracellular matrix. Marine biopolymer-based electrospun nanofibrous scaffolds with multifunctional characteristics and tunable mechanical properties now attract significant attention for biomedical applications, such as tissue engineering, drug delivery, and wound healing. The present review, covering the literature up to the end of 2021, highlights the advancements in the development of marine biopolymer-based electrospun nanofibers for their utilization as cell proliferation scaffolds, bioadhesives, release modifiers, and wound dressings.

Chitosan-based DDSs for pH/hypoxia dual-triggered DOX delivery: Facile morphology modulation for higher in vitro cytotoxicity

The morphology of the drug delivery systems (DDSs) has been recognized to play an important role in their phagocytosis, cellular interaction and distribution. However, it is a technical challenge to simply prepare the non-spherical nanoscaled DDSs. Here, a facile strategy was developed to fabricate the pH/hypoxia dual-responsive nanowires by adding the maleic acid (MAH) and PEG modified chitosan (PEG-SS-CS-MAH) into aqueous solution of DOX. Compared with the PEG-SS-CS-MAH/DOX nanoparticles (NPs) by adding DOX into the PEG-SS-CS-MAH solution, the PEG-SS-CS-MAH/DOX nanowires (NWs) possessed a higher drug loading capacity of 58% and better pH/hypoxia dual-triggered DOX release performance with higher drug release in the simulated tumor intracellular microenvironment but a much lower premature drug leakage in the simulated normal physiological medium. As a result, higher in vitro anti-tumor efficacy was achieved with the PEG-SS-CS-MAH/DOX NWs, demonstrating their promising potential for tumor chemotherapy.

Sandwich structure Aloin-PVP/Aloin-PVP-PLA/PLA as a wound dressing to accelerate wound healing

We have prepared a new type of Aloin/Polyvinylpyrrolidone (PVP)-Aloin/PVP/polylactic acid (PLA)-PLA sandwich nanofiber membrane (APP), to achieve a time-regulated biphasic drug release behavior, used for hemostasis, antibacterial activity and accelerated wound healing. We tested the water absorption capacity, water contact angle, tensile strength, thermogravimetric analysis, Fourier transform infrared spectroscopy and in vitro drug release of the prepared material, as well as analyzed the morphology of the nanofiber membrane with a scanning electron microscope. In the wound healing experiment, the wound healing rate of APP on the 15th day was 96.67%, and it demonstrated excellent antibacterial activity by the disc diffusion method, showing superior antibacterial activity against Gram-negative bacteria. The skin defect model on the back of mice showed that APP nanofibers significantly induced granulation tissue growth, collagen deposition and epithelial tissue remodeling. Current research shows that the prepared composite nanofibers can quickly stop bleeding and can effectively promote wound healing.

Flow chart for the preparation of “sandwich” nanofiber membranes.

Star-shaped poly(ε-caprolactones) with well-defined architecture as potential drug carriers

The present study reported on the potential application of star-shaped poly(?-caprolactones) with different number of arms as new drug delivery matrix. Linear and star-shaped PCL ibuprofen loaded microspheres were prepared using oil-in-water (o/w) solvent evaporation technique and characterized with FTIR, DSC, XRD and SEM analysis. High yield, encapsulation efficiency and drug loadings were obtained for all microspheres. FTIR analysis revealed the existence of interactions between polymer matrix and drug, while the DSC analysis suggested that drug was encapsulated in an amorphous form. SEM analysis confirmed that regular, spherical in shape star-shaped microspheres, with diameter between 80 to 90 ?m, were obtained, while quite larger microspheres, 110 ?m, were prepared from linear PCL. The advantage of using star-shaped PCL microspheres instead of linear PCL was seen from drug release profiles which demonstrated higher amount of drug released from star-shaped polymer matrix as a consequence of their branched, flexible structure. Microspheres prepared from the polymers with the most branched structure showed the highest amount of released drug after 24 h. Finally, cytotoxicity tests, performed using normal human fibroblasts (MRC5), indicated absence of cytotoxicity at lower concentrations of microspheres proving the great potential of star-shaped PCL systems in comparison to linear ones.

Lipid poly (ɛ-caprolactone) hybrid nanoparticles of 5-fluorouracil for sustained release and enhanced anticancer efficacy

AIMS

The present study aimed to develop and characterize poly (ɛ-caprolactone) (PCL) based lipid polymer hybrid nanoparticles for sustained delivery and in-vitro anti-cancer activity in MCF-7 and HeLa cells cancer cell line.

MATERIALS AND METHODS

The nanoprecipitation method was used for the development of 5-fluorouracil loaded lipid polymer hybrid nanoparticles (LPHNPs). The developed LPHNPs were characterized for physicochemical characteristics and the anti-cancer effect was evaluated in MCF-7 and HeLa cells.

SIGNIFICANT FINDINGS

Six formulations having fixed amount of drug and varied lipid, polymer and emulsifier concentrations were prepared. The particle size was in the range of 174 ± 4 to 267 ± 2.65 nm, entrapment efficiency (92.87 ± 0.594 to 94.13 ± 0.772%), negative zeta potential, optimum polydispersity index and spherical shape. FTIR analysis shows no chemical interaction among the formulation components, DSC analysis reveals the disappearance of 5-FU melting endotherm in the developed LPHNPs suggesting amorphization of 5-FU in the developed system, XRD analysis indicates successful encapsulation of the drug in the lipid polymer matrix. The in-vitro release shows a biphasic release pattern with an initial burst release followed by a sustained release profile for 72 h. The drug loaded LPHNPs exhibited a greater cytotoxic effect than 5-FU solution due to sustained release and increased cellular internalization. The acute toxicity study revealed the safety of the developed carrier system for potential delivery of chemotherapeutic agents.

SIGNIFICANCE

The developed LPHNPs of 5-fluorouracil will provide the sustained release behavior of 5-fluorouracil to maximize the therapeutic efficacy and minimize the dose related toxicity.

5FU-loaded PCL/Chitosan/Fe3O4 Core-Shell Nanofibers Structure: An Approach to Multi-Mode Anticancer System

Purpose: 5FU and Fe3O4 nanoparticles were encapsulated in core-shell Polycaprolactone/Chitosan nanofibers as a multi-mode anticancer system to study drug release sustainability. The structure of the core-shell drug delivery system was also optimized according to drug release behavior by artificial intelligence. Methods: The core-shell nanofibers were electrospun by a coaxial syringe. ANN was used for function approximation to estimate release parameters. A genetic algorithm was then used for optimizing the structure. Chemical assay of the optimized sample was performed by FTIR, XRD, and EDX. VSM test was conducted to measure the real amount of loaded magnetic nanoparticles. HepG2 cell cytotoxicity was studied and the results for the optimized samples with and without Fe3O4 after 72hrs were reported. Results: Feeding ratio of sheath to core and the amount of CS, Fe3O4, and 5FU had a statistical effect on nanofibers diameters, which were 300-450nm. The drug loading efficiency of these nanofibers was 65-86%. ANN estimated the release parameters with an error of 10%. The temperature increased about 5.6°C in the AMF of 216kA.m-1~300kHz and 4.8°C in the AMF of 154kA.m-1~400kHz after 20min. HepG2 cell cytotoxicity for the optimized samples with and without Fe3O4 after 72hrs were 39.7% and 38.8%, respectively. Conclusion: Since this core-shell drug release system was more sustainable compared to the blend structure despite the low half-life of 5FU, it is suggested to utilize it as post-surgical implants for various cancer treatments such as liver or colorectal cancer in the future. This system is capable of providing chemotherapy and hyperthermia simultaneously.

A review on allopathic and herbal nanofibrous drug delivery vehicles for cancer treatments

Drug delivery empowered with nanotechnology manifests to be a superior therapy to cancer. Electrospun nanofibers cocooning anti-cancerous drugs have shown tremendous cytotoxicity towards various tumor cells, including breast, brain, liver, and lung cancer cells. This pristine drug delivery system, according to literature, desists showing any undesirable effects on other parts of the body and bestows several other benefits. From nature-derived Curcumin to laboratory-made Doxorubicin, literature proclaims many such drugs used in nanofibrous drug delivery. Also, multi-drug delivery has been reported to exhibit enhanced properties. The present review exhibits the unrealized potential of nanofibrous drug delivery in chemotherapy.

Recent applications of electrical, centrifugal, and pressurised emerging technologies for fibrous structure engineering in drug delivery, regenerative medicine and theranostics

Advancements in technology and material development in recent years has led to significant breakthroughs in the remit of fiber engineering. Conventional methods such as wet spinning, melt spinning, phase separation and template synthesis have been reported to develop fibrous structures for an array of applications. However, these methods have limitations with respect to processing conditions (e.g. high processing temperatures, shear stresses) and production (e.g. non-continuous fibers). The materials that can be processed using these methods are also limited, deterring their use in practical applications. Producing fibrous structures on a nanometer scale, in sync with the advancements in nanotechnology is another challenge met by these conventional methods. In this review we aim to present a brief overview of conventional methods of fiber fabrication and focus on the emerging fiber engineering techniques namely electrospinning, centrifugal spinning and pressurised gyration. This review will discuss the fundamental principles and factors governing each fabrication method and converge on the applications of the resulting spun fibers; specifically, in the drug delivery remit and in regenerative medicine.

The Fabrication of Poly(Σ-caprolactone)-Poly(ethylene oxide) Sandwich Type Nanofibers Containing Sericin-Capped Silver Nanoparticles as an Antibacterial Wound Dressing

In this study, antibacterial, synthetic poly(Σ-caprolactone)-poly(ethylene oxide) (PCL-PEO) multilayer nanofibers were produced by an electrospinning method. The material was synthesized in 3 layers. The upper-lower protective layers were produced by PCL nanofibers and the intermediate layer was produced from PEO nanofiber containing sericin-capped silver nanoparticles (S-AgNPs). The electrospinning conditions in which nano-sized, smooth, bead-free fibers were obtained was determined to be an applied voltage of 20 kV, a flow rate of 8 μL/min and a distance between the collector and the needle tip of 22 cm for the PCL layer (dissolved at a 12% g/mL concentration in a chloroform:methanol (3:2) solvent mixture) layer. For the S-AgNPs doped PEO layer (dissolved at a 3.5% g/mL concentration in water), the corresponding conditions were determined to be 20 kV, 15 μL/min and 20 cm. To characterize the three-layer material that consisted of PCL and S-AgNPs doped PEO layers, FTIR and SEM analyses were performed, and the water retention capacity, in situ degradability and antibacterial activity of the material was investigated. According to SEM analysis, the fibers obtained were found to be nano-sized, smooth and bead-free and the average size of the nanofibers forming the PCL layer was 687 nm while the average size of the fibers forming the PEO layer was 98 nm. Antibacterial activity tests were performed using gram-positive (Staphylococcus aureus ATCC 6538) and gram-negative (Escherichia coli ATCC 25922) bacteria and the resulting biomaterial was found to have antimicrobial effect on both gram-negative and gram-positive bacteria. It was determined that the 3-layer material obtained in this study can be used as a wound dressing.

Recent updates in the polysaccharides-based Nano-biocarriers for drugs delivery and its application in diseases treatment: A review

With people's increasing awareness of diseases treatment, the researchers began to focus on drug delivery to the exact site of action at the optimal rate. Some researchers have proved that many nanostructures loaded with drugs are significantly better than conventional nanostructures. However, the materials from which the nanostructure determines its performance. To use it as a pharmaceutical ingredient, it must meet strict safety regulatory standards worldwide. Therefore, people's attention has paid to easily available natural substances. As far as we know, bioactive polysaccharides are excellent candidates for realizing these purposes. To be precise, due to the natural availability of polysaccharides, it has been widely used in the research of Nano-biocarriers loaded with drugs. Based on the above analysis, the nanomaterials developed through the laboratory have great potential for upgrading to market products. Therefore, it is of great significance to review the latest progress of polysaccharide-based Nano-biocarriers in drug delivery and their application in diseases treatment. In this work, we focused on the preparation of polysaccharides-based Nano-biocarriers, commonly used polysaccharides for preparing Nano-biocarriers, and drugs loaded on polysaccharides-based Nano-biocarriers to treat diseases. Shortly, polysaccharide-based Nano-biocarriers will be increasingly used in drug delivery and treatment of diseases.

New Strategies for Safe Cancer Therapy Using Electrospun Nanofibers: A Short Review

Electrospun nanofibers regarding their special features, including high drug loading capacity, high surface to volume area, flexibility, and ease of production and operation, are of great interest for being used in tissue engineering, and drug delivery approaches. In this context, several studies have been done for the production of biodegradable and biocompatible scaffolds containing different anticancer agents for fighting with solid tumors. Surprisingly, these scaffolds are able to deliver different combinations of drugs and agents, such as nanoparticles and release them in a time dependent manner. Here in this review, we summarize the principles of electrospinning and their uses in entrapment of drugs and anti-proliferative agents suitable for cancer therapy. The latest studies performed on treating cancer using electrospinning are mentioned and their advantages and disadvantages over conventional treatment methods are discussed.

Electrospun Fibres of Chitosan/PVP for the Effective Chemotherapeutic Drug Delivery of 5-Fluorouracil

Electrospun nanofibrous mats consisting of chitosan (CS) and polyvinylpyrrolidone (PVP) were constructed. Tuning of solution and process parameters was performed and resulted in an electrospun system containing a 6:4 ratio of PVP:CS. This is a significant increase in the proportion of spun CS on the previously reported highest ratio PVP:CS blend. SEM analysis showed that the nanofibrous mats with 4 wt% CS/6 wt% PVP (sample E) comprised homogenous, uniform fibres with an average diameter of 0.569 μm. XPS analysis showed that the surface of the samples consisted of PVP. Raman and FTIR analysis revealed intermolecular interactions (via H-bonding) between PVP and CS. In FTIR spectra, the contribution of chitosan to CS/PVP complexes was shown by the downshift of the C=O band and by the linear increase in intensity of C-O stretching in CS. XPS analysis showed a smaller shift at the binding energy 531 eV, which relates to the amide of the acetylated functional groups. The obtained results demonstrate a sensitivity of Raman and FTIR tests to the presence of chitosan in PVP:CS blend. The chemotherapy drug 5-Fu was incorporated into the constructs and cell viability studies were performed. WST-8 viability assay showed that exposure of A549 human alveolar basal epithelial cells to 10 mg/mL 5-Fu loaded fibres was most effective at killing cells over 24 h. On the other hand, the constructs with loading of 1 mg/mL of drug were not efficient at killing A549 human alveolar basal epithelial cells. This study showed that CS/PVP/5-Fu constructs have potential in chemotherapeutic drug delivery systems.

Preparation and characterization of polyurethane/chitosan/CNT nanofibrous scaffold for cardiac tissue engineering

Myocardial infarction of cardiomyocytes is a leading cause of heart failure (HF) worldwide. Since heart has very limited regeneration capacity, cardiac tissue engineering (TE) to produce a bioactive scaffold is considered. In this study, a series of polyurethane solutions (5-7%wt) in aqueous acetic acid were prepared using electrospinning. A variety of Polyurethane (PU)/Chitosan (Cs)/carbon nanotubes (CNT) composite nanofibrous scaffolds with random and aligned orientation were fabricated to structurally mimic the extracellular matrix (ECM). Electrospun nanofibers were then characterized using field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), water contact angle, degradation studies, tensile tests, electrical resistance measurement and cell viability assay. The biocompatibility of electrospun random and aligned nanofibrous scaffolds with H9C2 Cells was confirmed. The results revealed that fabricated PU/Cs/CNT composite nanofibrous scaffolds were electro-conductive and aligned nanofibers could be considered as promising scaffolds with nano-scale features for regeneration of infarcted myocardium.

In vitro and in vivo evaluation of a nanofiber wound dressing loaded with melatonin

Wound healing is a complicated process that takes a long time to complete. The three-layer nanofiber wound dressing containing melatonin is highly expected to show remarkable wound repair by reducing the wound healing time. In this study, chitosan (Cs)-polycaprolactone (PCL)/ polyvinylalcohol (PVA)-melatonin (MEL)/ chitosan-polycaprolactone three-layer nanofiber wound dressing was prepared by electrospinning for melatonin sustained release. The characteristics of the wound dressing were further evaluated. The wound dressing had a high water uptake after 24 h (401%), and the water contact angle results showed that it had hydrophilicity effect that supported the cell attachment. The wound healing effect of wound dressing was examined using a full-thickness excisional model of rat skin by the local administration of MEL. The gene expressions of transforming growth factor-beta (TGF-β1), alpha-smooth muscle actin (α-SMA), collagen type I (COL1A1), and collagen type III (COL3A1) were further studied. The histopathological evaluation showed the complete regeneration of the epithelial layer, remodeling of wounds, collagen synthesis, and reduction in inflammatory cells. The NF + 20% MEL significantly increased TGF-β1, COL1A1, COL3A1, and α-SMA mRNA expressions. This wound dressing may have a considerable potential as a wound dressing to accelerate the wound healing.

Design, fabrication, and optimization of a dual function three-layer scaffold for controlled release of metformin hydrochloride to alleviate fibrosis and accelerate wound healing

Abnormal wound healing caused by the over-expression of collagen and fibronectin leads to fibrosis, the major complication of all treatment modalities. A three-layer nanofiber scaffold was designed, optimized, and fabricated. This scaffold comprised two supportive polycaprolactone (PCL)-chitosan layers on the sides and a polyvinyl alcohol (PVA)-metformin hydrochloride (metformin-HCl) in the middle. The physico-chemical properties of scaffold, such as mechanical characteristics, degradation, swelling, and in-vitro drug release, were evaluated. The biological tests, including cell viability in response to metformin-HCl and Tween 80, scaffold biocompatibility, cell attachment, and antibacterial activity, were further conducted. The wound healing effect of scaffold loaded with metformin-HCl (MSc+Met) was assessed in donut-shaped silicone splints in rats. Histopathological and immunohistochemical evaluation as well as mRNA expression levels of fibrosis markers were also studied. SEM images indicated a uniform, bead-less morphology and high porosity. Surface modification of scaffold by Tween 80 improved the surface hydrophilicity and enhanced the adhesion and proliferation of fibroblasts. The scar area on day 15 in MSc+Met was significantly lower than that of other groups. Histopathological and immunohistochemical evaluation revealed that group MSc+Met was the best, having significantly lower inflammation, higher angiogenesis, the smallest scar width and depth, maximum epitheliogenesis score, and the most optimal modulation of collagen density. Local administration of metformin-HCl substantially down-regulated the expression of fibrosis-involved genes: transforming growth factor (TGF-β1), collagen type 1 (Col-I), fibronectin, collagen type 3 (Col-III), and alpha-smooth muscle actin (α-SMA). Inhibiting these genes alleviates scar formation but delays wound healing; thus, an engineered scaffold was used to prevent delay in wound healing. These results provided evidence for the first time to introduce an anti-fibrogenic slow-releasing scaffold, which acts in a dual role, both alleviating fibrosis and accelerating wound healing.

Recent Advances in Polymer Nanomaterials for Drug Delivery of Adjuvants in Colorectal Cancer Treatment: A Scientific-Technological Analysis and Review

Colorectal cancer (CRC) is the type with the second highest morbidity. Recently, a great number of bioactive compounds and encapsulation techniques have been developed. Thus, this paper aims to review the drug delivery strategies for chemotherapy adjuvant treatments for CRC, including an initial scientific-technological analysis of the papers and patents related to cancer, CRC, and adjuvant treatments. For 2018, a total of 167,366 cancer-related papers and 306,240 patents were found. Adjuvant treatments represented 39.3% of the total CRC patents, indicating the importance of adjuvants in the prognosis of patients. Chemotherapy adjuvants can be divided into two groups, natural and synthetic (5-fluorouracil and derivatives). Both groups can be encapsulated using polymers. Polymer-based drug delivery systems can be classified according to polymer nature. From those, anionic polymers have garnered the most attention, because they are pH responsive. The use of polymers tailors the desorption profile, improving drug bioavailability and enhancing the local treatment of CRC via oral administration. Finally, it can be concluded that antioxidants are emerging compounds that can complement today's chemotherapy treatments. In the long term, encapsulated antioxidants will replace synthetic drugs and will play an important role in curing CRC.