Engineered microstructure granules for tailored drug release rate

Biomineralization of bone tissue: calcium phosphate-based inorganics in collagen fibrillar organic matrices

BACKGROUND

Bone regeneration research is currently ongoing in the scientific community. Materials approved for clinical use, and applied to patients, have been developed and produced. However, rather than directly affecting bone regeneration, these materials support bone induction, which regenerates bone. Therefore, the research community is still researching bone tissue regeneration. In the papers published so far, it is hard to find an improvement in the theory of bone regeneration. This review discusses the relationship between the existing theories on hard tissue growth and regeneration and the biomaterials developed so far for this purpose and future research directions.

MAINBODY

Highly complex nucleation and crystallization in hard tissue involves the coordinated action of ions and/or molecules that can produce different organic and inorganic composite biomaterials. In addition, the healing of bone defects is also affected by the dynamic conditions of ions and nutrients in the bone regeneration process. Inorganics in the human body, especially calcium- and/or phosphorus-based materials, play an important role in hard tissues. Inorganic crystal growth is important for treating or remodeling the bone matrix. Biomaterials used in bone tissue regeneration require expertise in various fields of the scientific community. Chemical knowledge is indispensable for interpreting the relationship between biological factors and their formation. In addition, sources of energy for the nucleation and crystallization processes of such chemical bonds and minerals that make up the bone tissue must be considered. However, the exact mechanism for this process has not yet been elucidated. Therefore, a convergence of broader scientific fields such as chemistry, materials, and biology is urgently needed to induce a distinct bone tissue regeneration mechanism.

CONCLUSION

This review provides an overview of calcium- and/or phosphorus-based inorganic properties and processes combined with organics that can be regarded as matrices of these minerals, namely collagen molecules and collagen fibrils. Furthermore, we discuss how this strategy can be applied to future bone tissue regenerative medicine in combination with other academic perspectives.

Enhancement of aptamer immobilization using egg shell-derived nano-sized spherical hydroxyapatite for thrombin detection in neuroclinic

In the present study, we describe the sonochemical isolation of nano-sized spherical hydroxyapatite (nHA) from egg shell and application towards thrombin aptasensing. In addition to the sonochemical method, two conventional methods present in literature were carried out to perform a comparative study. Various analysis methods including Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), Energy-Dispersive Analysis of X-Rays (EDAX), and Thermal Gravimetric Analysis (TGA) have been applied for the characterization of nHA and its nanocomposite with marine-derived collagen isolated from Rhizostoma pulmo jellyfish. TEM micrographs revealed the sonochemically synthesized nHA nanoparticles to have a unique porous spherical shape with a diameter of approximately 60-80nm when compared to hydroxyapatite nanoparticles synthesized using the other two methods which had a typical needle shaped morphology. EDAX, XRD and FTIR results demonstrated that the obtained patterns belonged to hydroxyapatite. Electrochemical impedance spectroscopy (EIS) is the main analyzing technique of the developed thrombin aptasensor. The proposed aptasensor has a detection limit of 0.25nM thrombin. For clinical application of the developed aptasensor, thrombin levels in blood and cerebrospinal fluid (CSF) samples obtained from patients with Multiple Sclerosis, Myastenia Gravis, Epilepsy, Parkinson, polyneuropathy and healthy donors were analyzed using both the aptasensor and commercial ELISA kit. The results showed that the proposed system is a promising candidate for clinical analysis of thrombin.

Osteogenic efficacy of strontium hydroxyapatite micro-granules in osteoporotic rat model

Excessive demineralization in osteoporotic bones impairs its self-regeneration potential following a defect/fracture and is of great concern among the aged population. In this context, implants with inherent osteogenic ability loaded with therapeutic ions like Strontium (Sr²⁺) may bring forth promising outcomes. Micro-granular Strontium incorporated Hydroxyapatite scaffolds have been synthesized and in vivo osteogenic efficacy was evaluated in a long-term osteoporosis-induced aged (LOA) rat model. Micro-granules with improved surface area are anticipated to resorb faster and together with the inherent bioactive properties of Hydroxyapatite with the leaching of Strontium ions from the scaffold, osteoporotic bone healing may be promoted. Long-term osteoporosis-induced aged rat model was chosen to extrapolate the results to clinical osteoporotic condition in the aged. Micro-granular 10% Strontium incorporated Hydroxyapatite synthesized by wet precipitation method exhibited increased in vitro dissolution rate and inductively coupled plasma studies confirmed Strontium ion release of 0.01 mM, proving its therapeutic potential for osteoporotic applications. Wistar rats were induced to long-term osteoporosis-induced aged model by ovariectomy along with a prolonged induction period of 10 months. Thereafter, osteogenic efficacy of Strontium incorporated Hydroxyapatite micro-granules was evaluated in femoral bone defects in the long-term osteoporosis-induced aged model. Post eight weeks of implantation in vivo regeneration efficacy ratio was highest in the Strontium incorporated Hydroxyapatite implanted group (0.92 ± 0.04) compared to sham and Hydroxyapatite implanted group. Micro CT evaluation further substantiated the improved osteointegration of Strontium incorporated Hydroxyapatite implants from the density histograms. Thus, the therapeutical potential of micro-granular Strontium incorporated Hydroxyapatite scaffolds becomes relevant, especially as bone void fillers in osteoporotic cases of tumor resection or trauma.