Generation of a Hydroxyapatite Nanocarrier through Biomineralization Using Cell-Free Extract of Lactic Acid Bacteria for Antibiofilm Application

Diel variation of plankton in the highly impacted freshwater zone of Hooghly estuary in relation to ecological alteration

Plankton are promising ecological monitoring tool that responds quickly to any sort of aquatic ecological alteration, of which many of them are much susceptible to ecological variations. Therefore, monitoring shifts in plankton composition can indicate changes in water quality and aid to identify potential pollution sources. In the present study, the variation in plankton dynamics in relation to ecological variables were monitored in the freshwater zone of the Hooghly estuary from May 2020 to April 2021. The study was conducted in the interval of every six hours. i.e., at 6 A.M., 12 P.M., 6 P.M., and 12 A.M. The present finding revealed the occurrence of 54 phytoplankton and 20 zooplankton taxa/species. Diel variation revealed that among different time intervals, the highest abundance of phytoplankton was recorded 28,307 cells l-1 at 12 P.M, while the lowest was recorded 10,632 cells l-1 at 6 A.M. However, the highest zooplankton abundance was observed 804 ind l-1 at 6 A.M., and the lowest was recorded 156 ind l-1 at 6 P.M. The ANOVA (p < 0.05) analysis indicated significant diel variation for many planktonic genera. The CCA exhibited that most of the phytoplankton were influenced by multiple water quality variables such as temperature, turbidity, calcium, pH, salinity, DO, and nutrients. However, the majority of the zooplankton were affected by turbidity, total phosphorus, sulphate, calcium and available nitrogen. Significant seasonal variation in plankton composition has also been observed. The present study will help to determine the varying diel pattern of planktons in retort to alterations in the water quality parameters and varying ecological niches.

Hearing Reconstruction of Patients with Otitis Media Based on Hydroxyapatite Nanomaterials

In this study, we conducted experiments on surgical methods and selection of osseous bone materials to study the hearing reconstruction of otitis media patients. The use of complete Bi mastoid mastectomy in patients with combined tympanoplasty was revealed for the pure tone air conduction valve, bone auditory valve and air bone conduction difference, which were 63.5, 32.5 and 34.9 respectively in preoperative values, and 27.6, 21 and 8.3 in the postoperative values. In addition, it was shown by the results that the artificial osseous material is better for the postoperative hearing reconstruction. In conclusion, our data suggests that hydroxyapatite nanomaterials have a tremendously positive effect on hearing reconstruction in patients with otitis media, and will certainly become one of the best choices for artificial osseous bone materials.

Nanotechnology for Targeted Detection and Removal of Bacteria: Opportunities and Challenges

The emergence of nanotechnology has created unprecedented hopes for addressing several unmet industrial and clinical issues, including the growing threat so-termed "antibiotic resistance" in medicine. Over the last decade, nanotechnologies have demonstrated promising applications in the identification, discrimination, and removal of a wide range of pathogens. Here, recent insights into the field of bacterial nanotechnology are examined that can substantially improve the fundamental understanding of nanoparticle and bacteria interactions. A wide range of developed nanotechnology-based approaches for bacterial detection and removal together with biofilm eradication are summarized. The challenging effects of nanotechnologies on beneficial bacteria in the human body and environment and the mechanisms of bacterial resistance to nanotherapeutics are also reviewed.

2-Dodecylmalonic acid-mediated synthesis of mineralized hydroxyapatite amicable for bone cell growth on orthopaedic implant

The present study illustrates the use of 2-dodecylmalonic acid (MA) as a template in biomineralization-inspired synthesis of hydroxyapatite nanoparticles (HANPs). HANPs synthesized in presence of various concentrations of MA displayed varying particle size and shape. The smallest particle size (22-27 nm) was obtained for MA₂-HANP synthesized in presence of 37 µM MA. The critical micelle concentration (CMC) for MA at pH 9.0 relevant for mineralization was ∼35 µM. AFM analysis revealed that at a low concentration of 10 µM and pH 9.0, MA could generate oblong-shaped aggregates. At 40 µM, comparable to the concentration used to generate MA₂-HANP, the amphiphile self-assembled to form a spherical soft scaffold, which likely regulated spatial confinement of ions during mineralization and generated small size HANPs. Osteoblast-like MG-63 cells seeded on titanium wire (TW) coated with MA₂-HANP-incorporated collagen type I (H-TW) displayed enhanced cell proliferation, high expression of osteogenic differentiation marker genes (Col I, ALP, OCN and Runx2) and copious calcium mineral deposition after 14 days of growth. The nuanced role of the self-assembly process of an amphiphilic template in HANP mineralization unravelled in the present study can guide future scaffold design for biomineralization-inspired synthesis of HANPs tailored for bone tissue engineering applications.

Probiotic bacteria cell surface-associated protein mineralized hydroxyapatite incorporated in porous scaffold: In vitro evaluation for bone cell growth and differentiation

There is a high demand for synthesis of biocompatible hydroxyapatite nanoparticle (HANP), which is a key component in bone tissue engineering scaffolds. The present study describes a facile route of HANP synthesis through mineralization of the cell surface-associated protein (CSP) from the human probiotic lactic acid bacteria (LAB) Lactobacillus rhamnosus GG. CSP extract from the LAB (consisting of ~66 kDa, ~47 kDa, ~40 kDa and ~25 kDa protein) was mineralized to yield spindle-shaped HANPs having an average particle length of 371 nm as evidenced in FETEM analysis. CSP-mineralized HANPs (CSP-HANPs) were characterized by FTIR and BET analysis, while XRD and SAED analysis indicated their crystalline nature. Mechanistic studies suggested the key role of ~25 kDa CSP (F4SP) in mineralization. In contrast to CSP-HANPs, F4SP-mineralized crystalline HA was plate-shaped having an average length of 1.68 μm and breadth of 0.95 μm. HANP mineralization at the whole-cell (WC) level resulted in clusters of aggregated HANPs (WC-HANPs) adhering onto L. rhamnosus GG cells as evident in FETEM, FESEM and AFM analysis. FETEM analysis revealed that the desorbed WC-HANPs recovered by cell lysis were needle-shaped, with a particle size distribution of 70-110 nm. Given that CSP-HANPs were non-toxic to cultured HEK 293 cells and osteoblast-like MG-63 cells, chitosan-gelatin (CG) scaffold incorporated with 15% w/v CSP-HANP (H-CG) was generated and tested for bone cell growth. H-CG exhibited a favorable pore size distribution (160-230 μm), overall porosity (~84%) and biodegradation profile. H-CG scaffold was conducive to osteogenesis and rendered enhanced proliferation, alkaline phosphatase (ALP) activity, calcium mineralization and heightened marker gene expression (ALP, Col I, Runx2 and OCN) in seeded MG-63 cells. CSP sourced from a safe probiotic LAB is thus a viable and effective mineralization template for synthesis of biocompatible HANPs that can be leveraged for bone tissue engineering applications.

Biomineralization: An Opportunity and Challenge of Nanoparticle Drug Delivery Systems for Cancer Therapy

Biomineralization is a common process in organisms to produce hard biomaterials by combining inorganic ions with biomacromolecules. Multifunctional nanoplatforms are developed based on the mechanism of biomineralization in many biomedical applications. In the past few years, biomineralization-based nanoparticle drug delivery systems for the cancer treatment have gained a lot of research attention due to the advantages including simple preparation, good biocompatibility, degradability, easy modification, versatility, and targeting. In this review, the research trends of biomineralization-based nanoparticle drug delivery systems and their applications in cancer therapy are summarized. This work aims to promote future researches on cancer therapy based on biomineralization. Rational design of nanoparticle drug delivery systems can overcome the bottleneck in the clinical transformation of nanomaterials. At the same time, biomineralization has also provided new research ideas for cancer treatment, i.e., targeted therapy, which has significantly better performance.