Magnetically induced anisotropic structure in an injectable hydrogel for skeletal muscle regeneration.

Skeletal muscle integrity and its intrinsic aligned architecture are crucial for locomotion, postural support, and respiration functions, impacting overall quality of life. However, volumetric muscle loss (VML) can exceed intrinsic regenerative potential, leading to fibrosis and impairments. Autologous muscle grafting, the current gold standard, is constrained by tissue availability and success rates. Therefore, innovative strategies like cell-based therapies and scaffold-based approaches are needed. Our minimally invasive approach involves a tunable injectable hydrogel capable of achieving an aligned architecture post-injection via a low-intensity static magnetic field (SMF). Our hydrogel formulation uses gellan gum as the backbone polymer, enriched with essential extracellular matrix components such as hyaluronic acid and collagen type I, enhancing bio-functionality. To achieve an aligned architectural biomimicry, collagen type I is coupled with iron oxide magnetic nanoparticles, creating magnetic collagen bundles (MagC) that align within the hydrogel when exposed to a SMF. An extensive study was performed to characterize MagC and assess the hydrogel's stability, mechanical properties, and biological response in vitro and in vivo. The proposed system, fully composed of natural polymers, exhibited mechanical properties similar to human skeletal muscle and demonstrated effective biological performances, supporting its potential as a safe and patient-friendly treatment for VML.

Bioinspired oriented calcium phosphate nanocrystal arrays with bactericidal and osteogenic properties.

The global diffusion of antibiotic resistance poses a severe threat to public health. Addressing antibiotic-resistant infections requires innovative approaches, such as antibacterial nanostructured surfaces (ANSs). These surfaces, featuring ordered arrays of nanostructures, exhibit the ability to kill bacteria upon contact. However, most currently developed ANSs utilize bioinert materials, lacking bioactivity crucial for promoting tissue regeneration, particularly in the context of bone infections. This study introduces ANSs composed of bioactive calcium phosphate nanocrystals. Two distinct ANSs were created through a biomineralization-inspired growth of amorphous calcium phosphate (ACP) precursors. The ANSs demonstrated efficient antibacterial properties against both Gram-negative (P. aeruginosa) and Gram-positive (S. aureus) antibiotic resistant bacteria, with up to 75 % mortality in adhered bacteria after only 4 h of contact. Notably, the ANS featuring thinner and less oriented nano-needles exhibited superior efficacy attributed to simultaneous membrane rupturing and oxidative stress induction. Moreover, the ANSs facilitate the proliferation of mammalian cells, enhancing adhesion, spreading, and reducing oxidative stress. The ANSs displayed also significant bioactivity towards human mesenchymal stem cells, promoting colonization and inducing osteogenic differentiation. Specifically, the ANS with thicker and more ordered nano-needles demonstrated heightened effects. In conclusion, ANSs introduced in this work have the potential to serve as foundation for developing bone graft materials capable of eradicate site infections while concurrently stimulating bone regeneration. STATEMENT OF SIGNIFICANCE: Nanostructured surfaces with antibacterial properties through a mechano-bactericidal mechanism have shown significant potential in fighting antibiotic resistance. However, these surfaces have not been fabricated with bioactive materials necessary for developing devices that are both antibacterial and able to stimulate tissue regeneration. This study demonstrates the feasibility of creating nanostructured surfaces of ordered calcium phosphate nano-needles through a biomineralization-inspired growth. These surfaces exhibit dual functionality, serving as effective bactericidal agents against Gram-negative and Gram-positive antibiotic-resistant bacteria while also promoting the proliferation of mammalian cells and inducing osteogenic differentiation of human mesenchymal stem cells. Consequently, this approach holds promise in the context of bone infections, introducing innovative nanostructured surfaces that could be utilized in the development of antimicrobial and osteogenic grafts.

Contactless magnetically responsive injectable hydrogel for aligned tissue regeneration.

Cellular alignment plays a pivotal role in several human tissues, including skeletal muscle, spinal cord and tendon. Various techniques have been developed to control cellular alignment using 3D biomaterials. However, the majority of 3D-aligned scaffolds require invasive surgery for implantation. In contrast, injectable hydrogels provide a non-invasive delivery method, gaining considerable attention for the treatment of diverse conditions, including osteochondral lesions, volumetric muscle loss, and traumatic brain injury. We engineered a biomimetic hydrogel with magnetic responsiveness by combining gellan gum, hyaluronic acid, collagen, and magnetic nanoparticles (MNPs). Collagen type I was paired with MNPs to form magnetic collagen bundles (MCollB), allowing the orientation control of these bundles within the hydrogel matrix through the application of a remote low-intensity magnetic field. This resulted in the creation of an anisotropic architecture. The hydrogel mechanical properties were comparable to those of human soft tissues, such as skeletal muscle, and proof of the aligned hydrogel concept was demonstrated. In vitro findings confirmed the absence of toxicity and pro-inflammatory effects. Notably, an increased fibroblast cell proliferation and pro-regenerative activation of macrophages were observed. The in-vivo study further validated the hydrogel biocompatibility and demonstrated the feasibility of injection with rapid in situ gelation. Consequently, this magnetically controlled injectable hydrogel exhibits significant promise as a minimally invasive, rapid gelling and effective treatment for regenerating various aligned human tissues.

Advances in Bone Biology.

Bone is a unique type of mineralised connective tissue that can support and protect soft tissues, contain bone marrow, and allow movement [...].

RGD-tagging of star-shaped PLA-PEG micellar nanoassemblies enhances doxorubicin efficacy against osteosarcoma.

We developed cyclic RGD-tagged polymeric micellar nanoassemblies for sustained delivery of Doxorubicin (Dox) endowed with significant cytotoxic effect against MG63, SAOS-2, and U2-OS osteosarcoma cells without compromising the viability of healthy osteoblasts (hFOBs). Targeted polymeric micellar nanoassemblies (RGD-NanoStar@Dox) enabled Dox to reach the nucleus of MG63, SAOS-2, and U2-OS cells causing the same cytotoxic effect as free Dox, unlike untargeted micellar nanoassemblies (NanoStar@Dox) which failed to reach the nucleus and resulted ineffective, demonstrating the crucial role of cyclic RGD peptide in driving cellular uptake and accumulation mechanisms in osteosarcoma cells. Micellar nanoassemblies were obtained by nanoformulation of three-armed star PLA-PEG copolymers properly synthetized with and without decoration with the cyclic-RGDyK peptide (Arg-Gly-Asp-D-Tyr-Lys). The optimal RGD-NanoStar@Dox nanoformulation obtained by nanoprecipitation method (8 % drug loading; 35 % encapsulation efficiency) provided a prolonged and sustained drug release with a rate significantly lower than the free drug under the same experimental conditions. Moreover, the nanosystem preserved Dox from the natural degradation occurring under physiological conditions (i.e., dimerization and consequent precipitation) serving as a slow-release "drug reservoir" ensuring an extended biological activity over the time.

2D and 3D anticancer properties of C2-functionalised glucosamine-Pt (IV) prodrugs based on cisplatin scaffold.

A series of C2-functionalied Pt (IV) glycoconjugates based on glucosamine have been synthesised, characterised and tested as anticancer agents on a series of different 2D and 3D cancer cell lines. The carbohydrate will act as a targeted delivery system to improve the selectivity, exploiting the Warburg Effect and the GLUTs receptors that are overexpressed in most of the cancer cells. The hydroxyl at C2 of the carbohydrates does not participate in hydrogen bonding with the GLUTs receptors, making C2 an attractive position for drug conjugation as seen in literature. In this study, we use the amino functionality at the C2 position in glucosamine and Copper-catalysed Azide-Alkyne Cycloaddition "click" (CuAAC) reaction to connect the prodrug Pt (IV) scaffold to the carbohydrate. We have investigated complexes with different linker lengths, as well as acetyl protected and free derivatives. To the best of our knowledge, this study represents the first series of Pt (IV) glucosamine-conjugates functionalised at C2.

Osteosarcoma cell death induced by innovative scaffolds doped with chemotherapeutics.

Osteosarcoma (OS) cancer treatments include systemic chemotherapy and surgical resection. In the last years, novel treatment approaches have been proposed, which employ a drug-delivery system to prevent offside effects and improves treatment efficacy. Locally delivering anticancer compounds improves on high local concentrations with more efficient tumour-killing effect, reduced drugs resistance and confined systemic effects. Here, the synthesis of injectable strontium-doped calcium phosphate (SrCPC) scaffold was proposed as drug delivery system to combine bone tissue regeneration and anticancer treatment by controlled release of methotrexate (MTX) and doxorubicin (DOX), coded as SrCPC-MTX and SrCPC-DOX, respectively. The drug-loaded cements were tested in an in vitro model of human OS cell line SAOS-2, engineered OS cell line (SAOS-2-eGFP) and U2-OS. The ability of doped scaffolds to induce OS cell death and apoptosis was assessed analysing cell proliferation and Caspase-3/7 activities, respectively. To determine if OS cells grown on doped-scaffolds change their migratory ability and invasiveness, a wound-healing assay was performed. In addition, the osteogenic potential of SrCPC material was evaluated using human adipose derived-mesenchymal stem cells. Osteogenic markers such as (i) the mineral matrix deposition was analysed by alizarin red staining; (ii) the osteocalcin (OCN) protein expression was investigated by enzyme-linked immunosorbent assay test, and (iii) the osteogenic process was studied by real-time polymerase chain reaction array. The delivery system induced cell-killing cytotoxic effects and apoptosis in OS cell lines up to Day 7. SrCPC demonstrates a good cytocompatibility and it induced upregulation of osteogenic genes involved in the skeletal development pathway, together with OCN protein expression and mineral matrix deposition. The proposed approach, based on the local, sustained release of anticancer drugs from nanostructured biomimetic drug-loaded cements is promising for future therapies aiming to combine bone regeneration and anticancer local therapy.

Benzimidazoles Containing Piperazine Skeleton at C-2 Position as Promising Tubulin Modulators with Anthelmintic and Antineoplastic Activity.

Benzimidazole anthelmintic drugs hold promise for repurposing as cancer treatments due to their interference with tubulin polymerization and depolymerization, manifesting anticancer properties. We explored the potential of benzimidazole compounds with a piperazine fragment at C-2 as tubulin-targeting agents. In particular, we assessed their anthelmintic activity against isolated Trichinella spiralis muscle larvae and their effects on glioblastoma (U-87 MG) and breast cancer (MDA-MB-231) cell lines. Compound 7c demonstrated exceptional anthelmintic efficacy, achieving a 92.7% reduction in parasite activity at 100 µg/mL after 48 hours. In vitro cytotoxicity analysis of MDA-MB 231 and U87 MG cell lines showed that derivatives 7b, 7d, and 7c displayed lower IC50 values compared to albendazole (ABZ), the control. These piperazine benzimidazoles effectively reduced cell migration in both cell lines, with compound 7c exhibiting the most significant reduction, making it a promising candidate for further study. The binding mode of the most promising compound 7c, was determined using the induced fit docking-molecular dynamics (IFD-MD) approach. Regular docking and IFD were also employed for comparison. The IFD-MD analysis revealed that 7c binds to tubulin in a unique binding cavity near that of ABZ, but the benzimidazole ring was fitted much deeper into the binding pocket. Finally, the absolute free energy of perturbation technique was applied to evaluate the 7c binding affinity, further confirming the observed binding mode.

Development of Novel Pt(IV)-Carbohydrate Derivatives as Targeted Anticancer Agents against Osteosarcoma.

Despite the enormous importance of cisplatin as a chemotherapeutic agent, its application is impacted by dose-limiting side effects and lack of selectivity for cancer cells. Researchers can overcome these issues by taking advantage of the pro-drug nature of the platinum(IV) oxidation state, and by modifying the coordination sphere of the metal centre with specific vectors whose receptors are overexpressed in tumour cell membranes (e.g., carbohydrates). In this paper we report the synthesis of four novel carbohydrate-modified Pt(IV) pro-drugs, based on the cisplatin scaffold, and their biological activity against osteosarcoma (OS), a malignant tumour which is most common in adolescents and young adults. The carbohydrate-targeting vectors and Pt scaffold are linked using copper-catalysed azide-alkyne cycloaddition (CuAAC) chemistry, which is synonymous with mild and robust reaction conditions. The novel complexes are characterised using multinuclear 1D-2D NMR (1H, 13C and 195Pt), IR, HR-MS, Elem. Analyses, and CV. Cytotoxicity on 2D and 3D and cell morphology studies on OS cell lines, as well as non-cancerous human foetal osteoblasts (hFOBs), are discussed.

Fluorescent Carbon Dots from Food Industry By-Products for Cell Imaging.

Herein, following a circular economy approach, we present the synthesis of luminescent carbon dots via the thermal treatment of chestnut and peanut shells, which are abundant carbon-rich food industry by-products. As-synthesized carbon dots have excellent water dispersibility thanks to their negative surface groups, good luminescence, and photo-stability. The excitation-emission behaviour as well as the surface functionalization of these carbon dots can be tuned by changing the carbon source (chestnuts or peanuts) and the dispersing medium (water or ammonium hydroxide solution). Preliminary in vitro biological data proved that the samples are not cytotoxic to fibroblasts and can act as luminescent probes for cellular imaging. In addition, these carbon dots have a pH-dependent luminescence and may, therefore, serve as cellular pH sensors. This work paves the way towards the development of more sustainable carbon dot production for biomedical applications.

Influence of DNA Type on the Physicochemical and Biological Properties of Polyplexes Based on Star Polymers Bearing Different Amino Functionalities.

The interactions of two star polymers based on poly (2-(dimethylamino)ethyl methacrylate) with different types of nucleic acids are investigated. The star polymers differ only in their functionality to bear protonable amino or permanently charged quaternary ammonium groups, while DNAs of different molar masses, lengths and topologies are used. The main physicochemical parameters of the resulting polyplexes are determined. The influence of the polymer' functionality and length and topology of the DNA on the structure and properties of the polyelectrolyte complexes is established. The quaternized polymer is characterized by a high binding affinity to DNA and formed strongly positively charged, compact and tight polyplexes. The parent, non-quaternized polymer exhibits an enhanced buffering capacity and weakened polymer/DNA interactions, particularly upon the addition of NaCl, resulting in the formation of less compact and tight polyplexes. The cytotoxic evaluation of the systems indicates that they are sparing with respect to the cell lines studied including osteosarcoma, osteoblast and human adipose-derived mesenchymal stem cells and exhibit good biocompatibility. Transfection experiments reveal that the non-quaternized polymer is effective at transferring DNA into cells, which is attributed to its high buffering capacity, facilitating the endo-lysosomal escape of the polyplex, the loose structure of the latter one and weakened polymer/DNA interactions, benefitting the DNA release.

Electroconductive scaffolds based on gelatin and PEDOT:PSS for cardiac regeneration.

Electroconductive biomaterials have been emerged to support the recovery of the degenerated electrically conductive tissues, especially the cardiac ones after myocardial infarction. This work describes the development of electroconductive scaffolds for cardiac tissue regeneration by using a biocompatible and conductive polymer - i.e. poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) - combined with a biomimetic polymer network of gelatin. Our approach involves the use of dehydrothermal (DHT) treatment in vacuum conditions to fabricate suitably stable scaffolds without using any additional crosslinking agent. The resulting scaffolds mimic the Young modulus - an essential mechanical performance - of native cardiac tissue and are endowed with a well-interconnected porosity coupled with a good swelling ability and stability in physiological conditions. Additionally, the presence of PEDOT:PSS is able to enhance the electroconductivity of resulting materials. All the scaffolds are non-cytotoxic towards H9C2 cardiomyoblasts and the presence of PEDOT:PSS enhances cell adhesion - especially at early timeframes, an essential condition for a successful outcome after the implantation - proliferation, and spreading on scaffolds. Considering the permissive interaction of scaffolds with cardiomyoblasts, the present biomimetic and electroconductive scaffolds display potential applications as implantable biomaterials for regeneration of electroconductive tissues, especially cardiac tissue, and as a promising 3D tissue model for in vitro biomolecules screening.

Three-armed RGD-decorated starPLA-PEG nanoshuttle for docetaxel delivery.

A novel star-shaped amphiphilic copolymer based on three poly(lactide)-block-poly(ethylene glycol) (PLA-PEG) terminal arms extending from a glycerol multifunctional core was newly synthesized and decorated with the tumor-targeting ligand cyclic-RGDyK peptide (Arg-Gly-Asp-D-Tyr-Lys) to be eventually formulated in polymeric micelles incorporating a suitable anticancer drug (i.e., Docetaxel, DTX; drug loading 16 %, encapsulation efficiency 69 %). The biological profile of unloaded micelles (RGD-NanoStar) was studied on Human Adipose-derived Mesenchymal Stem Cells (Ad-MSCs) as health control, pointing out the absence of toxicity. Surprisingly, an unprecedented effect on cell viability was exerted by RGD-NanoStar, comparable to that of the free DTX, on tumoral MDA-MB 468 Human Breast Adenocarcinoma cells, specifically starting from 48 h of culture (about 40 % and 60 % of dead cells at 48 and 72 h, respectively, at all tested concentrations). RGD-NanoStar reduced the cell viability also of tumoral U87 Human Glioblastoma cells, compared to cells only, at 72 h (about 25 % of dead cells) demonstrating a time-dependent effect exerted by the highest concentrations. The effects of DTX-loaded micelles (RGD-NanoStar/DTX) on U87 and MDA-MB 468 cell lines were evaluated by MTT, cell morphology analysis, and scratch test. A compromised cell morphology was observed without significant difference between DTX-treated and RGD-NanoStar/DTX - treated cells, especially in U87 cell line. Although no apparent benefit emerged from the drug incorporation into the nanosystem by MTT assay, the scratch test revealed a statistically significant inhibition of tumoral cell migration on both cell lines, confirming the well-known role of DTX in inhibiting cell movements even when loaded on polymeric micelles. Specifically, only 43 µm distance was covered by U87 cells after 30 h culture with RGD-NanoStar/DTX (30 µg/mL) compared to 73 µm in the presence of free DTX at the same concentration; more interestingly, a total absence of MDA-MB 468 cell movements was detected at 30 h compared to about 50 µm distance covered by cells in the presence of free DTX (10 µg/mL). The stronger inhibitory activity on cell migration of RGD-NanoStar/DTX compared to the free drug in both cell lines at 30 h attested for a good ability of the drug-loaded nanocarrier to reduce tumor propagation and invasiveness, enhancing the typical effect of DTX on metastatization.

Graphene Oxide Nanoplatforms to Enhance Cisplatin-Based Drug Delivery in Anticancer Therapy.

Chemotherapeutics such as platinum-based drugs are commonly used to treat several cancer types, but unfortunately, their use is limited by several side effects, such as high degradation of the drug before entering the cells, off-target organ toxicity and development of drug resistance. An interesting strategy to overcome such limitations is the development of nanocarriers that could enhance cellular accumulation in target cells in addition to decreasing associated drug toxicity in normal cells. Here, we aim to prepare and characterize a graphene-oxide-based 2D nanoplatform functionalised using highly branched, eight-arm polyethylene-glycol, which, owing to its high number of available functional groups, offers considerable loading capacity over its linear modalities and represents a highly potent nanodelivery platform as a versatile system in cancer therapy. The obtained results show that the GO@PEG carrier allows for the use of lower amounts of Pt drug compared to a Pt-free complex while achieving similar effects. The nanoplatform accomplishes very good cellular proliferation inhibition in osteosarcoma, which is strictly related to increased cellular uptake. This enhanced cellular internalization is also observed in glioblastoma, although it is less pronounced due to differences in metabolism compared to osteosarcoma. The proposed GO@PEG nanoplatform is also promising for the inhibition of migration, especially in highly invasive breast carcinoma (i.e., MDA-MB-231 cell line), neutralizing the metastatic process. The GO@PEG nanoplatform thus represents an interesting tool in cancer treatment that can be specifically tailored to target different cancers.

Peptide-based targeted cancer therapeutics: Design, synthesis and biological evaluation.

Cancer is the leading cause for human mortality together with cardiovascular diseases. Abl (Abelson) tyrosine kinases play a fundamental role in transducing various signals that control proliferation, survival, migration and invasion in several cancers such as Chronic Myeloid Leukemia (CML), breast cancer and brain cancer. For these reasons Abl tyrosine kinases are considered important biological targets in drug discovery. In this study a series of lysine-based oligopeptides with expected Abl inhibitory activity were designed resembling the binding of FDA-approved drugs (i.e. of Imatinib and Nilotinib), synthesized, purified by High Performance Liquid Chromatography (HPLC), analyzed by mass spectrometry (MS) and biologically tested in vitro in CML (AR-230 and K-562), breast cancers (MDA-MB 231 and MDA-MB 468) and glioblastoma cell lines (U87 and U118). The solid-phase peptide synthesis (SPPS) by Fmoc (9-fluorenylmethoxycarbonyl) chemistry was used to synthesize target compounds. AutoDock Vina was applied for simulation binding to Abl. The biological activities were measured evaluating cytotoxic effect, induction of apoptosis and inhibition of cancer cells migration. The new peptides exhibited different concentration-dependent antiproliferative effect against the tumor cell lines after 72 h treatment. The most promising results were obtained with the U87 glioblastoma cell line where a significant reduction of the migration ability was detected with one compound (H-Lys1-Lys2-Lys3-NH2).

Additive-Free Gelatine-Based Devices for Chondral Tissue Regeneration: Shaping Process Comparison among Mould Casting and Three-Dimensional Printing.

Gelatine is a well-known and extensively studied biopolymer, widely used in recent decades to create biomaterials in many different ways, exploiting its molecular resemblance with collagen, the main constituent of the extra-cellular matrix, from which it is derived. Many have employed this biopolymer in tissue engineering and chemically modified (e.g., gelatin methacryloyl) or blended it with other polymers (e.g., alginate) to modulate or increase its performances and printability. Nevertheless, little is reported about its use as a stand-alone material. Moreover, despite the fact that multiple works have been reported on the realization of mould-casted and three-dimensional printed scaffolds in tissue engineering, a clear comparison among these two shaping processes, towards a comparable workflow starting from the same material, has never been published. Herein, we report the use of gelatine as stand-alone material, not modified, blended, or admixed to be processed or crosslinked, for the realization of suitable scaffolds for tissue engineering, towards the two previously mentioned shaping processes. To make the comparison reliable, the same pre-process (e.g., the gelatin solution preparation) and post-process (e.g., freeze-drying and crosslinking) steps were applied. In this study, gelatine solution was firstly rheologically characterized to find a formulation suitable for being processed with both the shaping processes selected. The realized scaffolds were then morphologically, phisico-chemically, mechanically, and biologically characterized to determine and compare their performances. Despite the fact that the same starting material was employed, as well as the same pre- and post-process steps, the two groups resulted, for most aspects, in diametrically opposed characteristics. The mould-casted scaffolds that resulted were characterized by small, little-interconnected, and random porosity, high resistance to compression and slow cell colonization, while the three-dimensional printed scaffolds displayed big, well-interconnected, and geometrically defined porosity, high elasticity and recover ability after compression, as well as fast and deep cell colonization.

Controlled Liposome Delivery from Chitosan-Based Thermosensitive Hydrogel for Regenerative Medicine.

This work describes the development of an injectable nanocomposite system based on a chitosan thermosensitive hydrogel combined with liposomes for regenerative medicine applications. Liposomes with good physicochemical properties are prepared and embedded within the chitosan network. The resulting nanocomposite hydrogel is able to provide a controlled release of the content from liposomes, which are able to interact with cells and be internalized. The cellular uptake is enhanced by the presence of a chitosan coating, and cells incubated with liposomes embedded within thermosensitive hydrogels displayed a higher cell uptake compared to cells incubated with liposomes alone. Furthermore, the gelation temperature of the system resulted to be equal to 32.6 °C; thus, the system can be easily injected in the target site to form a hydrogel at physiological temperature. Given the peculiar performance of the selected systems, the resulting thermosensitive hydrogels are a versatile platform and display potential applications as controlled delivery systems of liposomes for tissue regeneration.

Click Pt(IV)-Carbohydrates Pro-Drugs for Treatment of Osteosarcoma.

The selectivity vs. cancer cells has always been a major challenge for chemotherapeutic agents and in particular for cisplatin, one of the most important anticancer drugs for the treatment of several types of tumors. One strategy to overtake this challenge is to modify the coordination sphere of the metallic center with specific vectors whose receptors are overexpressed in the tumoral cell membrane, such as monosaccharides. In this paper, we report the synthesis of four novel glyco-modified Pt(IV) pro-drugs, based on cisplatin scaffold, and their biological activity against osteosarcoma (OS), a malignant tumor affecting in particular adolescents and young adults. The sugar moiety and the Pt scaffold are linked exploiting the Copper Azide Alkyne Cycloaddition (CUAAC) reaction, which has become the flagship of click chemistry due to its versatility and mild conditions. Cytotoxicity and drug uptake on three different OS cell lines as well as CSCs (Cancer Stem Cell) are described.

Magnetic and radio-labeled bio-hybrid scaffolds to promote and track in vivo the progress of bone regeneration.

This work describes the preparation, characterization and functionalization with magnetic nanoparticles of a bone tissue-mimetic scaffold composed of collagen and hydroxyapatite obtained through a biomineralization process. Bone remodeling takes place over several weeks and the possibility to follow it in vivo in a quick and reliable way is still an outstanding issue. Therefore, this work aims to produce an implantable material that can be followed in vivo during bone regeneration by using the existing non-invasive imaging techniques (MRI). To this aim, suitably designed biocompatible SPIONs were linked to the hybrid scaffold using two different strategies, one involving naked SPIONs (nMNPs) and the other using coated and activated SPIONs (MNPs) exposing carboxylic acid functions allowing a covalent attachment between MNPs and collagen molecules. Physico-chemical characterization was carried out to investigate the morphology, crystallinity and stability of the functionalized materials followed by MRI analyses and evaluation of a radiotracer uptake ([99mTc]Tc-MDP). Cell proliferation assays in vitro were carried out to check the cytotoxicity and demonstrated no side effects due to the SPIONs. The achieved results demonstrated that the naked and coated SPIONs are more homogeneously distributed in the scaffold when incorporated during the synthesis process. This work demonstrated a suitable approach to develop a biomaterial for bone regeneration that allows the monitoring of the healing progress even for long-term follow-up studies.

Recent Advances and Challenges in Gene Delivery Mediated by Polyester-Based Nanoparticles.

Gene therapy is a promising approach for the treatment of several diseases, such as chronic or viral infections, inherited disorders, and cancer. The cellular internalization of exogenous nucleic acids (NA) requires efficient delivery vehicles to overcome their inherent pharmacokinetic drawbacks, e.g. electrostatic repulsions, enzymatic degradation, limited cellular uptake, fast clearance, etc. Nanotechnological advancements have enabled the use of polymer-based nanostructured biomaterials as safe and effective gene delivery systems, in addition to viral vector delivery methods. Among the plethora of polymeric nanoparticles (NPs), this review will provide a comprehensive and in-depth summary of the polyester-based nanovehicles, including poly(lactic-co-glycolic acid) (PLGA) and polylactic acid (PLA) NPs, used to deliver a variety of foreign NA, e.g. short interfering RNA (siRNA), messenger RNA (mRNA), and plasmid DNA (pDNA). The article will review the versatility of polyester-based nanocarriers including their recent application in the delivery of the clustered, regularly-interspaced, short palindromic repeats/Cas (CRISPR/Cas) genome editing system for treating gene-related diseases. The remaining challenges and future trend of the targeted delivery of this revolutionary genome-editing system will be discussed. Special attention will be given to the pivotal role of nanotechnology in tackling emerging infections such as coronavirus disease 2019 (COVID-19): ground-breaking mRNA vaccines delivered by NPs are currently used worldwide to fight the pandemic, pushing the boundaries of gene therapy.