Publications by authors named "Ramesh Ayyala"

: The design of alternative antipathogenic sprays has recently attracted much attention due to the limitations of existing formulations, such as toxicity and low and narrow efficacy. Polyethyleneimine (PEI) is a great antimicrobial polymer against a wide range of pathogens, but toxicity limits its use. Here, betainized PEI (B-PEI) was synthesized to decrease the toxicity of PEI and protonated with citric acid (CA), boric acid (BA), and HCl to improve antimicrobial activity.

View Article and Find Full Text PDF

Purpose: Dry eye disease (DED) is a prevalent ocular surface disease that is conventionally characterized by tear film hyperosmolarity and instability. This review presents a summarized classification of DED, followed by a comprehensive discussion of the most recent topical and systemic medications and clinical recommendations for selecting the most appropriate option for each patient.

Methods: An extensive literature search was conducted on electronic databases, such as PubMed, Scopus, and Web of Science, using keywords including "dry eye syndrome," "ocular surface disease," "medical management," "artificial tears," "topical immunomodulators," and "meibomian gland dysfunction.

View Article and Find Full Text PDF

Photo-activatable antipathogenic carbon dots (CDs) were prepared by carbonization of citric acid and arginine (Arg) via 3 min microwave treatment for use in the eradication of common microorganisms. Nitrogen-doped Arg CDs were spherical in shape with a size range of 0.5 to 5 nm.

View Article and Find Full Text PDF

Carboxymethyl chitosan (CMCh) is a unique polysaccharide with functional groups that can develop positive and negative charges due to the abundant numbers of amine and carboxylic acid groups. CMCh is widely used in different areas due to its excellent biocompatibility, biodegradability, water solubility, and chelating ability. CMCh microgels were synthesized in a microemulsion environment using divinyl sulfone (DVS) as a crosslinking agent.

View Article and Find Full Text PDF
Article Synopsis
  • Cyclodextrins (CDs) are natural compounds with a hydrophobic core and a hydrophilic exterior; this study created three types (α-, β-, γ-) of CD particles using a novel crosslinking method.
  • The resulting particles are small (sub-10 µm), biocompatible, and mostly non-hemolytic, particularly with p(α-CD) and p(β-CD) showing over 95% cell viability.
  • The study also explored the interaction and loading of toxic and antioxidant substances (BPA and curcumin) in CDs, finding that β-CD formed the most stable complexes, and the particles allowed for controlled drug release.
View Article and Find Full Text PDF

Glycol chitosan (GC) is a chitosan (CH) derivative with improved water solubility with regards to CH which affords significant solubility advantages. In this study, microgels of GC as p(GC) were synthesized by a microemulsion technique at various crosslinking ratios e.g.

View Article and Find Full Text PDF

Chondroitin sulfate (CS), a well-known glycosaminoglycan, was physically crosslinked with Fe(III), Gd(III), Zn(II), and Cu(II) ions to obtain CS-Fe(III), CS-Gd(III), CS-Zn(II), and CS-Cu(II) polymeric particles for multipurpose biological applications. The CS-metal ion-containing particles in the micrometer to a few hundred nanometer size range are injectable materials for intravenous administration. The CS-metal ion-containing particles are safe biomaterials for biological applications because of their perfect blood compatibility and no significant cytotoxicity on L929 fibroblast cells up to a 10 mg/mL concentration.

View Article and Find Full Text PDF

Glycerol (Gly) is a well-known, FDA-approved molecule posing three hydroxyl groups. Since Gly is biocompatible, here, it was aimed to prepare poly(Glycerol) (p(Gly)) particles directly for the first time for the delivery of therapeutic agents. Micrometer-sized particles of p(Gly) were successfully synthesized via the micro-emulsion method with an average size of 14.

View Article and Find Full Text PDF

Hyaluronic acid/mannitol (HA/MN)-based particles were designed as mitomycin c (MMC) delivery vehicles through the crosslinking of 1:0, 3:1, 1:3, and 0:1 mole ratios of HA/MN to investigate their potential use in bladder cancer therapy. The HA/MN-MMC particles prepared by the microemulsion crosslinking method were of 0.5-10 μm size with a zeta potential value of -36.

View Article and Find Full Text PDF

Non-degradable, slightly degradable, and completely degradable micro/nanoparticles derived from chondroitin sulfate (CS) were synthesized through crosslinking reactions at 50%, 40%, and 20% mole ratios, respectively. The CS particles with a 20% crosslinking ratio show total degradation within 48 h, whereas 50% CS particles were highly stable for up to 240 h with only 7.0 ± 2.

View Article and Find Full Text PDF

Antifungal drug-loaded hyaluronic acid (HA) microgels using conjugation and encapsulation drug-loading techniques were utilized in the treatment of fungal keratitis. Natamycin (NAT) and amphotericin B (AMB) drugs were chemically linked to HA microgels by employing a chemical coupling agent to obtain conjugated (C-) HA:NAT and HA:AMB microgels. Also, these drugs were loaded into the HA microgel network during HA microgel preparation to attain encapsulated (E-) HA:NAT and HA:AMB microgels.

View Article and Find Full Text PDF

Hyaluronic acid (HA) was crosslinked with Gd(III) and Fe(III) ions rendering physically crosslinked HA-metal(III) microgels as magnetic resonance imaging (MRI) enhancing contrast agents. These HA-Gd(III) and HA-Fe(III) microgels are injectable with size range, 50-5000 nm in water. The same isoelectric point, pH 1.

View Article and Find Full Text PDF

Fungal corneal ulcers are an uncommon, yet challenging, cause of vision loss. In the United States, geographic location appears to dictate not only the incidence of fungal ulcers, but also the fungal genera most encountered. These patterns of infection can be linked to environmental factors and individual characteristics of fungal organisms.

View Article and Find Full Text PDF

Nanostructured fluorescent particles derived from natural molecules were prepared by a green synthesis technique employing a microwave method. The precursors citric acid (CA) and cysteine (Cys) were used in the preparation of S- and N-doped Cys carbon dots (Cys CDs). Synthesis was completed in 3 min.

View Article and Find Full Text PDF

Vision loss is a major complication in common ocular infections and diseases such as bacterial keratitis, age-related macular degeneration (AMD) and diabetic retinopathy (DR). The prevalence of such ophthalmic diseases represents an urgent need to develop safe, effective, and long-term treatments. Current therapies are riddled with drawbacks and limitations which calls for the exploration of alternative drug delivery mechanisms.

View Article and Find Full Text PDF

Here, the aim was to design and use a long-lasting antibiotic release system for prevention of postoperative infections in ophthalmic surgery. Ciprofloxacin and vancomycin-conjugated hyaluronic acid (HA) particles were prepared as drug carriers for sustained release of antibiotics. The antimicrobial effects of the released drugs were determined by disc-diffusion and macro-dilution tests at different times up to 2 weeks.

View Article and Find Full Text PDF

Hypothesis: Lactose (LAC) is a primary carbohydrate and energy source of milk has received intensive attention due to its' unique functional and nutritional properties. Many biological beneficences of LAC make it an appealing molecule to seek for designing functional interfaces. Therefore, crosslinked poly(lactose) (p(LAC)) microgel from lactose disaccharides for potential biomedical applications was pursued as biocolloids for the first time.

View Article and Find Full Text PDF

Purpose: To study surgical outcomes after combined phacoemulsification with either iStent implantation or goniotomy using the Kahook Dual Blade (KDB) with a minimum of 12 months of follow-up.

Patients And Methods: Patients with mild primary open-angle glaucoma who underwent phacoemulsification in combination with either iStent implantation or goniotomy using the KDB from 2011 to 2017 were included.

Results: In total, 48 eyes in the iStent group and 29 eyes in the KDB group were included with at least 12 months of follow-up.

View Article and Find Full Text PDF

We present here preparation of mechanically strong and biocompatible cryogel composites based on hyaluronic acid (HA) and halloysite nanotubes (HNTs) of various compositions, and their applications as scaffold for different cell growing media. Uniaxial compression tests reveal that the incorporation of HNTs into HA cryogels leads to a ~2.5-fold increase in their Young moduli, e.

View Article and Find Full Text PDF

Precis: Rabbit model studies suggested better morphology blebs with equal intraocular pressure (IOP) efficacy as a standard mitomycin C (MMC) trabeculectomy using a novel slow-release drug delivery antifibrotic system delivering small quantities of MMC and 5-fluorouracil (5-FU).

Purpose: To evaluate 2 different concentrations of biodegradable poly(lactic-co-glycolic acid) (PLGA) system with 5-FU and MMC (ElutiGLASS) for their ability to reduce fibrosis and compare the results with standard trabeculectomy with MMC in a rabbit model.

Materials And Methods: New Zealand albino rabbits (19) were divided into 3 groups (A, B, C) and standard trabeculectomy operation was performed in the right eye of each rabbit.

View Article and Find Full Text PDF

Purpose: To compare surgical outcomes of patients after phacoemulsification with goniosynechialysis (phaco/GSL) versus phaco with GSL and endocyclophotocoagulation (phaco/GSL/ECP) in patients with chronic angle closure glaucoma (CACG) through 12-month follow-up.

Methods: A retrospective, nonrandomized, comparative case series was performed. Patients with CACG who underwent phaco in combination with either GSL alone (group 1) or GSL with ECP with intracameral injection of kenalog (group 2) from 2011 to 2018 were included.

View Article and Find Full Text PDF

Porous and degradable hyaluronic acid (HA) microparticles was synthesized in a single step using different ratio of crosslinker, divinylsulfone (DVS) ranging between 2.5 and 100% mole ratio of HA repeating unit. HA particles less than 25% (≤10%) crosslinker ratio were found to be mesoporous and provided the highest surface area, calculated as 21.

View Article and Find Full Text PDF

Purpose: To report the safety and efficacy outcomes following micropulse transscleral cyclophotocoagulation (MPTSCPC) procedure in patients with uncontrolled glaucoma.

Materials And Methods: Longitudinal retrospective cohort, multicenter study. Patients with different types of glaucoma who underwent MPTSCPC with P3 probe between July 2015 and May 2017.

View Article and Find Full Text PDF

Purpose: Glaucoma drainage device (GDD) implantation can lead to corneal decompensation. We evaluated changes over time in oxygen tension and in the metabolic environment of the aqueous humor after GDD implantation in the rabbit eye.

Methods: Ahmed Glaucoma Valves were implanted in the left eyes of eight male New Zealand white rabbits.

View Article and Find Full Text PDF