A Review on the Driving Forces in the Formation of Bioactive Molecules-Loaded Prolamin-Based Particles

Prolamin-based particles loaded with bioactive molecules have attracted widespread attention from scientists due to their novel properties in chemistry, physics, and biology. In the self-assembly process of biopolymer-based nanocapsules, noncovalent interactions are the main driving forces for reducing bulk materials to the nanoscale and controlling the release of bioactive molecules. This article reviews the types of interaction forces, binding strength, binding active sites, molecular orientation, and binding affinity that affect the release profile of bioactive molecules during the preparation of protein stabilizer particles. Different preparation formulations, the use of different biopolymers, the inherent nature of the loaded bioactive molecules, and external factors (including pH, biopolymer concentration, temperature, salt, ultrasonication, and atmospheric cold plasma treatment) lead to different types and strengths of intra- and intermolecular interactions. Strategies, such as pH, ultrasonication, and atmospheric cold plasma, to change the protein conformation are key to improving the binding strength between proteins and bioactive substances or stabilizers. This review provides some guidance for scientists and technicians dedicated to improving loading efficiency, delaying release, enhancing colloidal stability, and exploring the binding behavior among proteins, stabilizers, and bioactive molecules.

Kaempferol-loaded bioactive glass-based scaffold for bone tissue engineering: in vitro and in vivo evaluation

Due to the increasing prevalence of bone disorders among people especially in average age, the future of treatments for osseous abnormalities has been illuminated by scaffold-based bone tissue engineering. In this study, in vitro and in vivo properties of 58S bioactive glass-based scaffolds for bone tissue engineering (bare (B.SC), Zein-coated (C.SC), and Zein-coated containing Kaempferol (KC.SC)) were evaluated. This is a follow-up study on our previously published paper, where we synthesized 58S bioactive glass-based scaffolds coated with Kaempferol-loaded Zein biopolymer, and characterized from mostly engineering points of view to find the optimum composition. For this aim, in vitro assessments were done to evaluate the osteogenic capacity and biological features of the scaffolds. In the in vivo section, all types of scaffolds with/without bone marrow-derived stem cells (BMSC) were implanted into rat calvaria bone defects, and potential of bone healing was assessed using imaging, staining, and histomorphometric analyses. It was shown that, Zein-coating covered surface cracks leading to better mechanical properties without negative effect on bioactivity and cell attachment. Also, BMSC differentiation proved that the presence of Kaempferol caused higher calcium deposition, increased alkaline phosphatase activity, bone-specific gene upregulation in vitro. Further, in vivo study confirmed positive effect of BMSC-loaded KC.SC on significant new bone formation resulting in complete bone regeneration. Combining physical properties of coated scaffolds with the osteogenic effect of Kaempferol and BMSCs could represent a new strategy for bone regeneration and provide a more effective approach to repairing critical-sized bone defects.

Zein Microparticles and Nanoparticles as Drug Delivery Systems

Zein is a natural, biocompatible, and biodegradable polymer widely used in the pharmaceutical, biomedical, and packaging fields because of its low water vapor permeability, antibacterial activity, and hydrophobicity. It is a vegetal protein extracted from renewable resources (it is the major storage protein from corn). There has been growing attention to producing zein-based drug delivery systems in the recent years. Being a hydrophobic biopolymer, it is used in the controlled and targeted delivery of active principles. This review examines the present-day landscape of zein-based microparticles and nanoparticles, focusing on the different techniques used to obtain particles, the optimization of process parameters, advantages, disadvantages, and final applications.

Preparation and characterization of 58S bioactive glass based scaffold with Kaempferol-containing Zein coating for bone tissue engineering

The aim of this study was to prepare a porous scaffold out of 58S bioactive glass as the bare and coated with Zein to improve mechanical properties and acting as a carrier for Kaempferol controlled delivery. Porosity and morphology, mechanical properties, drug release behavior, bioactivity, cell attachment, and biodegradation of the scaffolds were evaluated accordingly. Obtained results indicated that the scaffolds coated by (7wt/v %) Zein solution, showed the highest mechanical strength (3.06 ± 0.4 MPa) and desirable porous morphology. These scaffolds could support bioactivity, cell attachment, and provide sustained drug release in the safe range of Kaempferol concentration confirmed via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide analysis. Overall, this study showed that the Zein-coated scaffold possesses superior properties rather than bare scaffold, and the scaffolds coated with 7wt/v % Zein solution could be considered as appropriate scaffolds for bone regeneration.

Local Drug Delivery Based Treatment Approaches for Effective Management of Periodontitis

Background:

Periodontal disease is an immuno-inflammatory condition of tissues that surround and hold the teeth. It is the disease which succeeds in all races, groups and both genders. Almost 10 to15% of the global population gets suffered from severe periodontitis as per WHO reports. Periodontal disease may likely cause other systemic diseases such as cardiovascular disease and pre-term low birth weight infants. Mechanical removal of plaques and calculus deposits from supra and subgingival environment is the backbone of periodontal treatment till date whereas complete elimination of these deleterious agents is quite unrealistic as the pocket depth increases.

Recent Approaches:

Recently controlled local drug delivery application is more encouraging in comparison to systemic approach as it mainly targets to enhance the therapeutic efficacy by maintaining site-specificity, avoiding first pass metabolism, reduction in gastrointestinal (GI) side effects and decreasing the dose. Several drugs such as antiseptics and antibiotics alongwith various carriers are being formulated as local drug delivery systems for effective management of the disease. Various local delivery systems reported are fibers, films, strips, compacts, injectables, microparticles, vesicular carriers, gels and nanoparticles. These local carriers provide effective prolonged treatment at the site of infection at reduced doses. This review enlightens detailed pathophysiology and various phases of periodontitis, challenges in treatment of disease and various antimicrobial agents (along with their marketed formulations) used. The main emphasis of the review is to cover all carrier systems developed so far for local delivery application in the effective management of periodontitis, as a patient compliant drug therapy.

Local drug delivery systems in the management of periodontitis: A scientific review

Periodontitis (PD) is a microbial disease of tooth supporting tissues that results in progressive destruction of surrounding soft and hard tissues with eventual tooth mobility and exfoliation. Perioceutics, which includes the delivery of therapeutic agents via systemic and local means as an adjunct to mechanical therapy has revolutionized the arena of periodontal therapy. Selection of a right antimicrobial agent with appropriate route of drug administration is the key to successful periodontal therapy. Irrigating systems, fibers, gels, strips, films, microparticles, nanoparticles and low dose antimicrobial agents are some of the local drug delivery systems (LDDS) available in the field, which aims to deliver antimicrobial agents to sub-gingival diseased sites with minimal or no side-effects on other body sites. The present review aim to summarize the current state-of-the-art technology on LDDS in periodontal therapy ensuring the the practitioners are able to choose LDD agents which are custom made for a specific clinical condition.

Effect of Polymeric Microparticles Loaded With Catechin on the Physicochemical Properties of an Adhesive System

The objective of this study was to synthesize and characterize epigallocatechin-3-gallate (EGCG)-loaded/poly(D-L lactide-co-glycolide) acid (PLGA) microparticles, evaluate their effects on degree of conversion and release assay of adhesives, and subsequently to examine the resin-dentin bond strength of two EGCG formulations (free EGCG or loaded into PLGA microparticles) applied as a pretreatment or incorporated into an adhesive system. The formulations were prepared according to a PLGA:EGCG ratio of 16:1 using the spray-drying technique. The size and polydispersity index were determined by light scattering in aqueous dispersion. The degree of conversion (%DC) and release assay were assessed by Fourier transform infrared spectroscopy and ultraviolet-visible spectrophotometer, respectively. Subsequently, 45 third molars were divided into five groups (n=9) according to the different EGCG application modes and prepared for bond strength testing in a universal testing machine. Results demonstrated no statistically significant difference among the DC means after the PLGA microparticles were loaded with EGCG. For the release assay, the 1.0% PLGA/EGCG group presented better results after being elected for use in the bond strength test. The resin-dentin bond strengths of the experimental groups after 12 months of water storage were significantly higher than in the control group. EGCG could improve the durability of the resin-dentin bond over time and promote a new era for adhesive dentistry with the concept of controlled release.

Biopharmaceutical Activities Related to Ellagic Acid, Chitosan, and Zein and Their Improvement by Association

Ellagic acid (EA) has demonstrated several biological properties, such as antioxidant, antimicrobial, and enzymatic inhibition. Zein and chitosan (CHI) are natural polymers whose biological potential has also gained attention. Therefore, this paper aimed to evaluate the antimicrobial, antioxidant, anticollagenase, and antielastase properties of EA, zein, and chitosan isolated or in combination. The microdilution method was used to assess the minimum inhibitory and bactericide concentrations. The antioxidant activity was determined using the 2,2-diphenyl-1-picryl-hydrazila free radical scavenging method. The anticollagenase and antielastase activities were evaluated by specific colorimetric tests. EA has shown inhibitory activity against Staphylococcus aureus and Pseudomonas aeruginosa together with an antioxidant IC₅₀ of 0.079 mg/mL. EA also showed significant collagenase and elastase inhibition. Zein has shown antimicrobial and antioxidant activities itself and enhanced sinergically the antioxidant activity and the antimicrobial activity against P. aeruginosa when combined with EA. CHI increased sinergically the inhibitory activity of EA against both bacterial strains, while showed itself an acceptable antimicrobial activity. ¹ H saturation transfer-difference nuclear magnetic resonance experiment confirmed the formation of a complex between EA and zein that could be related with the improvement on its biological performance over the individual compounds, while no chemical interaction was detected between CHI and EA. PRACTICAL APPLICATION: The results reinforce the potential of ellagic acid in combination with zein and/or chitosan as an antimicrobial, antienzimatic, and antioxidant agent. Those findings reinforce the use of these substances, protecting this bioactive from degradation and/or improving the functional characteristics and biopharmaceutical properties.

Advanced drug delivery systems for local treatment of the oral cavity

Good oral health is of major importance for general health and well-being. Several innovative drug delivery systems have been developed for the local treatment and prevention of various diseases in the oral cavity. However, there are currently few optimal systems and many therapeutic challenges still remain, including low drug efficacy and retention at targeted site of action. The present review provides an insight into the latest drug delivery strategies for the local treatment and prevention of the four most common oral pathologies, namely, dental caries, periodontitis, oral mucosal infections and oral cancer. The potential of bioadhesive formulations, nanoparticulate platforms, multifunctional systems and photodynamic methodologies to improve therapy and prophylaxis in future local applications for the oral cavity will be discussed.

Electrospun Zein/PCL Fibrous Matrices Release Tetracycline in a Controlled Manner, Killing Staphylococcus aureus Both in Biofilms and Ex Vivo on Pig Skin, and are Compatible with Human Skin Cells

Purpose

To investigate the destruction of clinically-relevant bacteria within biofilms via the sustained release of the antibiotic tetracycline from zein-based electrospun polymeric fibrous matrices and to demonstrate the compatibility of such wound dressing matrices with human skin cells.

Methods

Zein/PCL triple layered fibrous dressings with entrapped tetracycline were electrospun. The successful entrapment of tetracycline in these dressings was validated. The successful release of bioactive tetracycline, the destruction of preformed biofilms, and the viability of fibroblast (FEK4) cells were investigated.

Results

The sustained release of tetracycline from these matrices led to the efficient destruction of preformed biofilms from Staphylococcus aureus MRSA252 in vitro, and of MRSA252 and ATCC 25923 bacteria in an ex vivo pig skin model using 1 × 1 cm square matrices containing tetracycline (30 μg). Human FEK4 cells grew normally in the presence of these matrices.

Conclusions

The ability of the zein-based matrices to destroy bacteria within increasingly complex in vitro biofilm models was clearly established. An ex vivo pig skin assay showed that these matrices, with entrapped tetracycline, efficiently kill bacteria and this, combined with their compatibility with a human skin cell line suggest these matrices are well suited for applications in wound healing and infection control.

Mechanical properties and drug release behavior of PCL/zein coated 45S5 bioactive glass scaffolds for bone tissue engineering application

This article presents data related to the research article entitled "The effect of coating type on mechanical properties and controlled drug release of PCL/zein coated 45S5 bioactive glass scaffolds for bone tissue engineering" [1]. We provide data on mechanical properties, in vitro bioactivity and drug release of bioactive glass (BG) scaffolds coated by poly (ε-caprolactone) (PCL) and zein used as a controlled release device for tetracycline hydrochloride (TCH). By coating the BG scaffolds with PCL or PCL/zein blend the mechanical properties of the scaffolds were substantially improved, i.e., the compressive strength increased from 0.004±0.001 MPa (uncoated BG scaffolds) to 0.15±0.02 MPa (PCL/zein coated BG scaffolds). A dense bone-like apatite layer formed on the surface of PCL/zein coated scaffolds immersed for 14 days in simulated body fluid (SBF). The data describe control of drug release and in vitro degradation behavior of coating by engineering the concentration of zein. Thus, the developed scaffolds exhibit attractive properties for application in bone tissue engineering research.

Zein/polycaprolactone electrospun matrices for localised controlled delivery of tetracycline

We report the controlled release of the antibiotic tetracycline (Tet) from triple-layered (3L) electrospun matrices consisting of zein or a zein/PCL blend, where the drug was loaded into the central layer with the two outer layers acting as diffusion barriers. These fibrous matrices successfully encapsulated Tet and efficiently inhibited the growth of a clinical isolate, the methicillin-resistant Staphylococcus aureus strain MRSA252, as demonstrated in a modified Kirby-Bauer disc assay over 5 days. Whilst untreated zein fibres are unstable in an aqueous environment, rapidly shrinking due to plasticisation and film formation, blending zein with PCL stabilised the electrospun matrices and prevented them from shrinking. These 3L formulations display sustained antibiotic release and provide a proof of concept for zein-based polymeric matrices as wound dressings to treat or prevent bacterial infection. This is the first demonstration of the controlled release of a clinically used antibiotic from electrospun zein-based matrices.

In situ forming implants for periodontitis treatment with improved adhesive properties

Novel in situ forming implants are presented showing a promising potential to overcome one of the major practical hurdles associated with local periodontitis treatment: limited adhesion to the surrounding tissue, resulting in accidental expulsion of at least parts of the implants from the patients' pockets. This leads to high uncertainties in the systems' residence times at the site of action and in the resulting drug exposure. In the present study, the addition of different types and amounts of plasticizers (acetyltributyl citrate and dibutyl sebacate) as well as of adhesive polymers (e.g., cellulose derivatives such as hydroxypropyl methylcellulose) is shown to allow for a significant increase in the stickiness of poly(lactic-co-glycolic acid)-based implants. The systems are formed in situ from N-methyl pyrrolidone-based liquid formulations. Importantly, at the same time, good plastic deformability of the implants can be provided and desired drug release patterns can be fine-tuned using several formulation tools. The antimicrobial activity of this new type of in situ forming implants, loaded with doxycycline hyclate, was demonstrated using the agar well diffusion method and multiple Streptococcus strains isolated from the oral microflora of patients suffering from periodontitis.

Use of 1H NMR STD, waterLOGSY, and Langmuir monolayer techniques for characterization of drug-zein protein complexes

Zein is a protein based natural biopolymer containing a large amount of nonpolar amino acids, which has shown the ability to form aggregates and entrap solutes, such as drugs and amino acids to form stable protein-drug complexes. In this work, π-A isotherm, NMR, and Dynamic light scattering were used to detect the formation of protein aggregates and the affinity between zein and two different drugs: tetracycline and indomethacin. An effective interaction of zein and the two drugs was evidenced by means of liquid NMR reinforced by means of changes in the surface pressure by π-A isotherm. The effective interactions zein/drugs under air/water interface were evidenced as a change in the surface pressure of the π-A isotherm of zein in the presence of drug solutions. The presence of tetracycline in the subphase decreased the area occupied by the monolayer at the expanded region until pressures of 12 mN/m were the areas became similar, but indomethacin produces an increment of the area in both expanded and collapsed region. The feasible methodology employed, focused in the functionality of the protein-drug interaction, can be very promising in the drug delivery field.