Publications by authors named "Nenad L Ignjatovic"

This study focuses on the designing and characterization, and anticancer evaluation of chitosan-based nanoparticles (NPs) loaded (enriched) with a Biginelli hybrid compound (BH). NPs based on chitosan (CH) or chitosan oligosaccharide lactate (CHOL), are carefully designed to encapsulate a tetrahydropyrimidine derivative (BH) with already proven anticancer properties. The formulations were evaluated for their physicochemical properties, including particle size distribution and morphology, using techniques such as infrared spectroscopy, scanning electron microscopy, and X-ray diffraction.

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Titanium (Ti) is widely used in medical and dental implants. Calcium phosphate (CPs) coatings enhance Ti implants' osteoinductive properties, and additives further improve these coatings. Recently, a nano amorphous calcium phosphate (nACP) coating decorated with chitosan oligolactate (ChOL) and selenium (Se) showed immunomodulatory effects.

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The aim of this work is in situ anodization/anaphoretic deposition of a nano amorphous calcium phosphate (ACP)/chitosan oligosaccharide lactate (ChOL) multifunctional hybrid coating decorated with selenium (Se) on a titanium substrate and in vivo investigation of its immunomodulatory and anti-inflammatory effect. Investigating phenomena at the implant-tissue interface of interest for controlled inflammation and immunomodulation was also the aim of the research. In our earlier research, we designed coatings based on ACP and ChOL on titanium with anticorrosive, antibacterial and biocompatible properties, while in the presented results we show that selenium addition makes this coating an immunomodulator.

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Chemically modified steroids have a long history as anti-neoplastic drugs. Incorporation of a lactone moiety in the steroid nucleus, as in previously obtained 3β-acetoxy-17-oxa-17a-homoandrost-5-en-16-one (A) and 3β-hidroxy-17-oxa-17a-homoandrost-5-en-16-one (B), often results in enhanced anticancer properties. In this work, chitosan-based (Ch) nanoparticles were created and loaded with potent anticancer steroidal compounds, A and B.

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The aim of this work was to investigate corrosion resistivity, bioactivity, and antibacterial activity of novel nano-amorphous calcium phosphate (ACP) potentially multifunctional composite coatings with and without chitosan oligosaccharide lactate (ChOL), ACP + ChOL/TiO and ACP/TiO ACP + ChOL/TiO, respectively, on the titanium substrate. The coatings were obtained by new single-step in situ anodization of the substrate to generate TiO and the anaphoretic electrodeposition process of ACP and ChOL. The obtained coatings were around 300 ± 15 μm thick and consisted of two phases, namely, TiO and hybrid composite phases.

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Taking advantage of the flexibility of the apatite structure, nano- and micro-particles of hydroxyapatite (HAp) were doped with different combinations of rare earth ions (RE = Gd, Eu, Yb, Tm) to achieve a synergy among their magnetic and optical properties and to enable their application in preventive medicine, particularly diagnostics based on multimodal imaging. All powders were synthesized through hydrothermal processing at T ≤ 200 °C. An X-ray powder diffraction analysis showed that all powders crystallized in P6/m space group of the hexagonal crystal structure.

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Reconstruction of bone defects with the use of biomaterials based on hydroxyapatite (HAp) has been a popular approach in medicine and dentistry. Most often the process of new bone formation is analyzed with the focus only on the region of the reconstructed defect. The effects of the therapy on distant organs have been rarely reported in the literature, especially not in synergy with the exposure to other bioactive chemicals.

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Article Synopsis
  • Researchers developed a new cancer inhibitor using a compound called derivative A that was effectively captured in nano-sized carriers made from hydroxyapatite coated with chitosan-PLGA.
  • The study demonstrated that these spherical carriers target lung cells when administered intravenously and investigated their selective toxicity towards cancerous lung cells compared to healthy cells.
  • Results showed that the carriers were more toxic to cancerous cells, exhibiting nearly three times greater cytotoxicity, while maintaining over 80% viability of healthy cells with lower concentrations of derivative A.
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Low targeting efficiency and fast metabolism of antineoplastic drugs are hindrances to effective chemotherapies and there is an ongoing search for better drugs, but also better carriers. Steroid derivatives, 3β-hydroxy-16-hydroxymino-androst-5-en-17-one (A) and 3β,17β-dihydroxy-16-hydroxymino-androst-5-ene (B) as cancer growth inhibitors were chemically synthesized and captured in a carrier composed of hydroxyapatite (HAp) nanoparticles coated with chitosan oligosaccharide lactate (ChOLS). The only difference between the two derivatives is that A has a carbonyl group at the C17 position of the five-membered ring and B has a hydroxyl.

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Article Synopsis
  • The study explores a drug delivery system using hydroxyapatite nanoparticles coated with chitosan-poly(d,l)-lactide-co-glycolide (HAp/Ch-PLGA) that target lung cells, specifically for cancer treatment.
  • The researchers loaded these particles with a chemotherapeutic agent, 17β-hydroxy-17α-picolyl-androst-5-en-3β-yl-acetate, which showed selective anticancer activity against lung cancer cells while preserving healthy cells.
  • Results indicated a sustained release of the drug and demonstrated significant cytotoxic effects on cancer cells while maintaining high viability for normal lung cells, positioning the composite particles as a promising platform for targeted cancer therapies.
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In the field of oral implantology the loss of bone tissue prevents adequate patient care, and calls for the use of synthetic biomaterials with properties that resemble natural bone. Special attention is paid to the risk of infection after the implantation of these materials. Studies have suggested that some nanocontructs containing metal ions have antimicrobial properties.

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Most drug delivery systems as treatment modalities for osteomyelitis have not been evaluated for resistant infections. Tigecycline (TG) is an antimicrobial agent that could be used in the treatment of multi-drug-resistant orthopedic infections. The objective of this in vitro study has been to determine what dosage of TG causes changes in the morphology and number of osteoblasts.

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Unlabelled: Simulated body fluid (SBF) is an artificial fluid which has ionic composition and ionic concentration similar to human blood plasma.

Purpose: This paper compares the interaction between the nanomaterial containing calcium phosphate/poly-dl-lactide-co-glycolide (N-CP/PLGA) and SBF, in order to investigate whether and to what extent inorganic ionic composition of human blood plasma leads to the aforementioned changes in the material.

Methods: N-CP/PLGA was incubated for 1, 2, 3, and 5 weeks in SBF.

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In this article, synthesis and application of calcium phosphate/poly-DL-lactide-co-glycolide (CP/PLGA) composite biomaterial in particulate form, in which each CP granule/particle is coated with PLGA, are described. Two types of the particulate material having different particle sizes were synthesized: one with an average particle diameter between 150 and 250 mum (micron-sized particles, MPs) and the other with an average particle diameter smaller than 50 nm (nanoparticles, NPs). A comparative in vivo analysis was done by reconstructing defects in osteoporotic alveolar bones using both composites.

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The purpose of the study presented in this paper has been to examine the possibility of the synthesis of a new nanoparticulate system for controlled and systemic drug delivery with double effect. In the first step, a drug is released from bioresorbable polymer; in the second stage, after resorption of the polymer, non-bioresorbable calcium phosphate remains the chief part of the particle and takes the role of a filler, filling a bone defect. The obtained tigecycline-loaded calcium-phosphate(CP)/poly(DL-lactide-co-glycolide)(PLGA) nanoparticles contain calcium phosphate coated with bioresorbable polymer.

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