Development of a Thermoresponsive Polymeric Composite Film Using Cross-Linked β-Cyclodextrin Embedded with Carbon Quantum Dots as a Transdermal Drug Carrier

Synthesis and drug release kinetics of ciprofloxacin from polyacrylamide/dextran/carbon quantum dots (PAM/Dex/CQD) hydrogels

Sustainable release of drug by utilizing β-cyclodextrin (β-CD) based inclusion complex (IC) is the prime objective of the present work. Herein, polyacrylamide/dextran containing carbon quantum dots (PAM/Dex/CQD) nanocomposite hydrogels are prepared by in situ polymerization of acrylamide. The incorporation of CQD triggers the change in orientation of the PAM/Dex polymeric chains to result the formation of stacked surface morphology of the hydrogel. The average particle size of CQD is found to be 4.13 nm from HRTEM analysis. As-synthesized nanocomposite hydrogel exhibits an optimum swelling ratio of 863 % in aqueous medium. The cytotoxicity study is conducted on HeLa cells by taking up to 2 μM concentration of the prepared nanocomposite hydrogel demonstrate 78 % cell viability. In present study, ciprofloxacin (Cipro) is taken as model drug that achieves release of 64.15 % in 32 h from β-Cipro@PAM/Dex/CQD hydrogels in acidic medium. From theoretical study, release rate constants, R2, Akaike information criterion (AIC) and model selection criterion (MSC) are computed to determine the best fitted kinetics model. Peppas-Sahlin model is the best fitted kinetics model for β-Cipro@PAM/Dex/CQD and concluded that the release of Cipro follows Fickian drug diffusion mechanism in acidic medium.

Evolution of Transdermal Drug Delivery Devices and Novel Microneedle Technologies: A Historical Perspective and Review

The history of transdermal drug delivery is as old as humankind. Transdermal drug delivery has undergone three generations of development; the third generation has involved the use of medical devices and instruments. This review provides a historical perspective on the primary approaches employed in the three generations of transdermal drug delivery. In addition, we explore some of the recently developed transdermal techniques that are deemed promising in the field of drug delivery. We discuss how advances in these techniques have led to the development of devices for the delivery of a therapeutically effective amount of drug across human skin and highlight the limitations of the first- and second-generation drug delivery tools. As such, a review of the performance of these techniques and the toxicity of the devices used in transdermal drug delivery are considered. In the last section of the review, a discussion of the fabrication and operation of different types of microneedles is presented. The applications of microneedles in the sensing and delivery of various therapeutic agents are described in detail. Furthermore, an overview of the efficacy of microneedles as emerging tools for the controlled release of drugs is presented.

Supramolecular Chemistry of Carbon-Based Dots Offers Widespread Opportunities

Carbon dots are an emerging class of nanomaterials that has recently attracted considerable attention for applications that span from biomedicine to energy. These photoluminescent carbon nanoparticles are defined by characteristic sizes of <10 nm, a carbon-based core and various functional groups at their surface. Although the surface groups are widely used to establish non-covalent bonds (through electrostatic interactions, coordinative bonds, and hydrogen bonds) with various other (bio)molecules and polymers, the carbonaceous core could also establish non-covalent bonds (ππ stacking or hydrophobic interactions) with π-extended or apolar compounds. The surface functional groups, in addition, can be modified by various post-synthetic chemical procedures to fine-tune the supramolecular interactions. Our contribution categorizes and analyzes the interactions that are commonly used to engineer carbon dots-based materials and discusses how they have allowed preparation of functional assemblies and architectures used for sensing, (bio)imaging, therapeutic applications, catalysis, and devices. Using non-covalent interactions as a bottom-up approach to prepare carbon dots-based assemblies and composites can exploit the unique features of supramolecular chemistry, which include adaptability, tunability, and stimuli-responsiveness due to the dynamic nature of the non-covalent interactions. It is expected that focusing on the various supramolecular possibilities will influence the future development of this class of nanomaterials.

Chemical modification of β-cyclodextrin towards hydrogel formation

β-CD is a cyclic oligosaccharide, which has trunked cone like structure. The unique structure makes it efficient for numerous applications. Though, the native β-CD has many issues like low solubility, absence of sufficient functionalities and lower complexation ability with guest molecules. One of the most effective paths to increase the efficiency of cyclodextrins is the generation of polycyclodextrins. In this perspective article, we have summarized the recent reports on the synthetic methods towards the modification of β-CD. Besides, this article reviews the current improvements of two types of β-CD centered supramolecular hydrogels: one is supramolecular hydrogels prepared from CD-based poly(pseudo)rotaxanes and the other is supramolecular hydrogels developed through the host-guest interaction between small guest molecules and CDs. The Polycyclodextrins have established noteworthy applications in several areas ranging from adsorbents for organic pollutants removal to effective carriers of bioactive agents.

pH-Responsive Copolymeric Network Gel Using Methacrylated β-Cyclodextrin for Controlled Codelivery of Hydrophilic and Hydrophobic Drugs

In medical science, sometimes two drugs with different solubilities are simultaneously required in combination to treat various diseases. Herein, a pH-responsive, copolymeric, antioxidant, biocompatible, and chemically crosslinked network gel is prepared to explore its capability as a matrix for controlled release of both hydrophobic [ibuprofen (IB)] and hydrophilic [tetracycline hydrochloride (TCH)] drugs, simultaneously. This three-dimensional β-CD-Meth-cl-(PHPMA-co-PAAc) network hydrogel is synthesized via two steps: (I) methacrylation of β-cyclodextrin and (II) grafting of poly(hydroxypropyl methacrylate) and poly(acrylic acid), followed by crosslinking of poly(ethylene glycol) diacrylate onto the backbone of methacrylated β-cyclodextrin (β-CD-Meth). The successful synthesis of the hydrogel is confirmed using several physiochemical characterizations. The β-CD-Meth-cl-(PHPMA-co-PAAc) hydrogel has an excellent network-like surface morphology. The potential pH-responsive high swelling behavior and excellent shrinking features suggest the reversible nature of the synthesized gel. Besides, rheological analyses affirm its excellent viscoelastic nature. This network gel is biodegradable and its non-cytotoxic nature toward human dermal fibroblast cells is demonstrated. Moreover, the dual drug release pattern from the copolymer under both in vitro and in vivo conditions portrays that this hydrogel has superior ability to be used as a controlled release matrix for both hydrophobic and hydrophilic drugs (TCH and IB) with varying solubilities concurrently.

β-Cyclodextrin-Based Ultrahigh Stretchable, Flexible, Electro- and Pressure-Responsive, Adhesive, Transparent Hydrogel as Motion Sensor

In the present work, a multiple-stimuli-responsive hydrogel has been synthesized via polymerization of acrylamide (AAm) and N-hydroxy methyl acrylamide (HMAm) on β-cyclodextrin (β-CD). The synthesized hydrogel β-CD-g-(pAAm/pHMAm) exhibited various striking features like ultrahigh stretchability (>6000%), flexibility, stab resistivity, self-recoverability, electroresponsiveness, pressure-responsiveness, adhesiveness, and high transparency (>90%). Besides, the hydrogel has demonstrated enhanced biocompatibility, UV resistance, and thermoresponsive shape memory behaviors. On the basis of these attractive characteristics of the hydrogel, a flexible pressure sensor for the real-time monitoring of human motion with superior biocompatibility and transparency was fabricated. Moreover, due to the nanofibrillar surface morphology of the β-CD-g-(pAAm/pHMAm) hydrogel, the sensor based on the gel exhibited high sensitivity (0.053 kPa^-1 for 0-3.3 kPa). The flexible sensor demonstrates very fast response time (130 ms-210 ms) with adequate stability (5000 cycles). Interestingly, the sensor can rapidly sense both robust (index finger and wrist) motions as well as tiny (swallowing and phonation) physiological actions. In addition, this adhesive hydrogel patch also acts as a potential carrier for the sustained topical release of (∼80.8% in 48 h) the antibiotic drug gentamicin sulfate.

The UCST phase transition of a dextran based copolymer in aqueous media with tunable thermoresponsive behavior

A hydrogen bonded UCST polymer has been developed by grafting of methacrylamide and acrylic acid on dextran via free radical polymerization.

Poly(N-vinyl imidazole) Cross-Linked β-Cyclodextrin Hydrogel for Rapid Hemostasis in Severe Renal Arterial Hemorrhagic Model

A unique facile process has been adopted for fast assembly of a poly(N-vinyl imidazole) cross-linked β-cyclodextrin hydrogel through microwave-assisted free radical polymerization, using N,N'-methylenebis(acrylamide) cross-linker. The copolymer possesses positive surface charge, one of the characteristic properties of an ideal hemostatic hydrogel. The functionalized imidazole-based hydrogel demonstrates rapid, superior blood coagulation kinetics under in vitro and in vivo conditions. On application to a major renal arterial hemorrhagic model, this hydrogel shows better blood clotting kinetics, leading to complete hemostasis in as few as ∼144 ± 7 s. Additionally, 350 μL of whole blood was clotted instantly, in ∼35 s, and therefore, reinforcing its hemostatic potential. The hydrogel demonstrates excellent biocompatibility, when seeded with human dermal fibroblast cells, retaining the native property of its predecessor. In addition, the hydrogel presents excellent hemocompatibility when tested with whole blood with the highest hemolytic ratio of 1.07 ± 0.05%. Moreover, it also demonstrates potential as a carrier for sustained release of an anesthetic drug, lidocaine hydrochloride monohydrate (∼83% in 24 h). The rapid hemostatic behavior of the hydrogel is coupled with its cytocompatibility and hemocompatibilty properties along with controlled drug release characteristics. These behaviors evidently demonstrate it to be an excellent alternative for a superior hemostatic material for severe hemorrhagic conditions.

A Novel Method for Preparation of Carrageenan/Fish Scale Collagen/Allopurinol Biocomposite Film

Biopolymers such as carrageenan or collagen can be used as carriers for loading a drug to enhance a drug’s bioavailability. In this work, allopurinol was loaded on a carrageenan/collagen blend and the carrageenan/collagen/allopurinol (CCA) biocomposite films were prepared using the ionic gelation method combined with the 3D printing method using carrageenan/collagen/allopurinol gel as a 3D printing ink material. The advantages of the 3D printing method are the ease in shaping the design of films and the ease in controlling the thickness of films. The results of infrared (IR) spectroscopy and field emission scanning electron microscopy (FESEM) analyses showed that the CCA biocomposite films have a regular structure, and the functional groups of components in the biocomposites can interact with each other. After 30 minutes of immersion in distilled water and pH buffer solution, the biocomposite films swelled and disintegrated. The carrageenan/collagen blend can control the release of allopurinol in simulated body fluids. In addition, the drug release kinetic models reflecting the release process of allopurinol from CCA biocomposite films in simulated body fluids have also been calculated.

Dual functions of pH-sensitive cation Zr-MOF for 5-Fu: large drug-loading capacity and high-sensitivity fluorescence detection

Nanomaterials, as carriers of small molecular drugs, have been a focal point in recent years. In this work, a carbazolyl functionalized metal-organic framework, UiO-67-CDC, was successfully synthesized employing the ligand 9H-carbazole-2,7-dicarboxylic acid (9H-2,7-CDC). Postsynthetic approaches targeted the cationization and replacement of the Lewis base carbazole site with two methyl groups, resulting in the positively charged skeleton, which has proven to be a promising carrier for the anticancer drug 5-fluorouracil (5-Fu). The prepared cationic framework UiO-67-CDC-(CH3)2 showed moderately high surface area, hierarchical pore structures, and positive surface characteristics, which effectively and selectivity encapsulated the electron-rich 5-Fu molecules through electrostatic attraction, with a relatively high loading of up to 56.5% (wt%). The drug delivery in simulated blood environment (pH = 7.4) exhibited a more effective release, demonstrating a physiological pH-responsive sustained release. Significantly, the electron-deficient Zr-MOF itself, as a kind of high-sensitivity fluorescence detector, has a unique fluorescence "turn-on" effect with 5-Fu. These results pave the way towards designing surface-engineered MOF materials of interest in drug delivery and fluorescent sensing applications.