Physicochemical Properties of Inorganic and Hybrid Hydroxyapatite-Based Granules Modified with Citric Acid or Polyethylene Glycol.

This study delves into the physicochemical properties of inorganic hydroxyapatite (HAp) and hybrid hydroxyapatite-chitosan (HAp-CTS) granules, also gold-enriched, which can be used as aggregates in biomicroconcrete-type materials. The impact of granules' surface modifications with citric acid (CA) or polyethylene glycol (PEG) was assessed. Citric acid modification induced increased specific surface area and porosity in inorganic granules, contrasting with reduced parameters in hybrid granules. PEG modification resulted in a slight increase in specific surface area for inorganic granules and a substantial rise for hybrid granules with gold nanoparticles. Varied effects on open porosity were observed based on granule type. Microstructural analysis revealed increased roughness for inorganic granules post CA modification, while hybrid granules exhibited smoother surfaces. Novel biomicroconcretes, based on α-tricalcium phosphate (α-TCP) calcium phosphate cement and developed granules as aggregates within, were evaluated for compressive strength. Compressive strength assessments showcased significant enhancement with PEG modification, emphasizing its positive impact. Citric acid modification demonstrated variable effects, depending on granule composition. The incorporation of gold nanoparticles further enriched the multifaceted approach to enhancing calcium phosphate-based biomaterials for potential biomedical applications. This study demonstrates the pivotal role of surface modifications in tailoring the physicochemical properties of granules, paving the way for advanced biomicroconcretes with improved compressive strength for diverse biomedical applications.

Novel Double Hybrid-Type Bone Cements Based on Calcium Phosphates, Chitosan and Citrus Pectin.

In this work, the influence of the liquid phase composition on the physicochemical properties of double hybrid-type bone substitutes was investigated. The solid phase of obtained biomicroconcretes was composed of highly reactive α-tricalcium phosphate powder (α-TCP) and hybrid hydroxyapatite/chitosan granules (HA/CTS). Various combinations of disodium phosphate (Na2HPO4) solution and citrus pectin gel were used as liquid phases. The novelty of this study is the development of double-hybrid materials with a dual setting system. The double hybrid phenomenon is due to the interactions between polycationic polymer (chitosan in hybrid granules) and polyanionic polymer (citrus pectin). The chemical and phase composition (FTIR, XRD), setting times (Gillmore needles), injectability, mechanical strength, microstructure (SEM) and chemical stability in vitro were studied. The setting times of obtained materials ranged from 4.5 to 30.5 min for initial and from 7.5 to 55.5 min for final setting times. The compressive strength varied from 5.75 to 13.24 MPa. By incorporating citrus pectin into the liquid phase of the materials, not only did it enhance their physicochemical properties, but it also resulted in the development of fully injectable materials featuring a dual setting system. It has been shown that the properties of materials can be controlled by using the appropriate ratio of citrus pectin in the liquid phase.

Study on ßTCP/P(3HB) Scaffolds-Physicochemical Properties and Biological Performance in Low Oxygen Concentration.

The search for new materials for bone regenerative purposes is still ongoing. Therefore, we present a series of newly constructed composites based on ß tricalcium phosphate (ßTCP) and poly(3-hydroxybutyrate) bacteria-derived biopolymer (P(3HB)) in the form of 3D scaffolds with different pore sizes. To improve the polymer attachment to the ßTCP surface, the etching of ceramic sinters, using citric acid, was applied. As expected, pre-treatment led to the increase in surface roughness and the creation of micropores facilitating polymer adhesion. In this way, the durability and compressive strength of the ceramic-polymer scaffolds were enhanced. It was confirmed that P(3HB) degrades to 3-hydroxybutyric acid, which broadens applications of developed materials in bone tissue engineering as this compound can potentially nourish surrounding tissues and reduce osteoporosis. Moreover, to the best of our knowledge, it is one of the first studies where the impact of ßTCP/P(3HB) scaffolds on mesenchymal stem cells (MSCs), cultured in lowered (5%) oxygen concentration, was assessed. It was decided to use a 5% oxygen concentration in the culture to mimic the conditions that would be found in damaged bone in a living organism during regeneration. Scaffolds enabled cell migration and sufficient flow of the culture medium, ensuring high cell viability. Furthermore, in composites with etched ßTCP, the MSCs adhesion was facilitated by hydrophilic ceramic protrusions which reduced hydrophobicity. The developed materials are potential candidates for bone tissue regeneration. Nevertheless, to confirm this hypothesis, in vivo studies should be performed.

Mindreading and metacognition patterns in patients with borderline personality disorder: experimental study.

Current psychopathology attempts to understand personality disorders in relation to deficits in higher cognition such as mindreading and metacognition. Deficits in mindreading are usually related to limitations in or a complete lack of the capacity to understand and attribute mental states to others, while impairments in metacognition concern dysfunctional control and monitoring of one's own processes. The present study investigated dysfunctional higher cognition in the population of patients with borderline personality disorder (BPD) by analyzing the accuracy of metacognitive judgments in a mindreading task [reading the mind in the eyes Test (RMET)] and a subsequent metacognitive task based on self-report scales: a confidence rating scale (CR) versus a post-decision wagering scale (PDW). It turned out that people from the BPD group scored lower in the RMET. However, both groups had the same levels of confidence on the PDW scale when giving incorrect answers in the RMET test. As initially hypothesized, individuals with BPD overestimated their confidence in incorrect answers, regardless of the type of metacognitive scales used. The present findings indicate that BPD individuals show dysfunctional patterns between instances of mindreading and metacognition.

COVID-19 pandemic fear, life satisfaction and mental health at the initial stage of the pandemic in the largest cities in Poland.

The study investigated whether the level of life satisfaction and general mental health was associated with COVID-19 worries at the initial stage of the COVID-19 pandemic in Poland. A cross-sectional observational study using an online questionnaire was conducted between 19 March and 27 April 2020, i.e. at the beginning of the epidemic in Poland. The study participants were residents of Poland over the age of 18 years. A total of 412 completed responses were received. The majority of respondents were women (75%), 84% respondents were mentally healthy and did not have any diagnosis of mental illnesses. Sixty-eight percent respondents indicated that they had been worried about the COVID-19 pandemic for the average of 21.75 days (SD +-16), while the median period from the onset of epidemic in Poland (20 March) to the participation in the study was 11 days. The main domains of concern included: death of loved ones (75%), severe course of illness in loved ones (72%), healthcare failure (64%), consequences of the pandemic at an individual and social level (64% and 63%, respectively). There was a significant medium decrease in the level of happiness and life satisfaction during the COVID-19 epidemic (p <.001).

Physicochemical and Biological Characterisation of Diclofenac Oligomeric Poly(3-hydroxyoctanoate) Hybrids as ß-TCP Ceramics Modifiers for Bone Tissue Regeneration.

Nowadays, regenerative medicine faces a major challenge in providing new, functional materials that will meet the characteristics desired to replenish and grow new tissue. Therefore, this study presents new ceramic-polymer composites in which the matrix consists of tricalcium phosphates covered with blends containing a chemically bounded diclofenac with the biocompatible polymer-poly(3-hydroxyoctanoate), P(3HO). Modification of P(3HO) oligomers was confirmed by NMR, IR and XPS. Moreover, obtained oligomers and their blends were subjected to an in-depth characterisation using GPC, TGA, DSC and AFM. Furthermore, we demonstrate that the hydrophobicity and surface free energy values of blends decreased with the amount of diclofenac modified oligomers. Subsequently, the designed composites were used as a substrate for growth of the pre-osteoblast cell line (MC3T3-E1). An in vitro biocompatibility study showed that the composite with the lowest concentration of the proposed drug is within the range assumed to be non-toxic (viability above 70%). Cell proliferation was visualised using the SEM method, whereas the observation of cell penetration into the scaffold was carried out by confocal microscopy. Thus, it can be an ideal new functional bone tissue substitute, allowing not only the regeneration and restoration of the defect but also inhibiting the development of chronic inflammation.

Influence of Selected Surfactants on Physicochemical Properties of Calcium Phosphate Bone Cements.

The influence of the three nonionic surface active agents such as Tween 20, Tween 80, and Tetronic 90R4 on hydrolysis, setting reaction, microstructure, and mechanical properties of alpha tricalcium phosphate (α-TCP) based materials was determined. The study revealed that the addition of any of the surfactants mentioned above slightly prolonged the setting time of the tested cements (up to 5 min). On the other hand, it was found that surfactants influence the long-term hydrolysis reaction. The addition of surfactants also affected the microstructure of the final materials, especially after incubation in a simulated body fluid. Surface active agents also had an impact on mechanical behavior of the obtained cements. Sorbitan esters, Tween 20 and Tween 80, decreased compressive strength in comparison to the reference material (6.56 ± 1.59 MPa) to 3.54 ± 1.18 and 3.68 ± 1.03 MPa, respectively. Interestingly, Tetronic 90R4, never used before as an additive to calcium phosphate bone cements (CPCs) caused a 2-fold increase of this value (up to 13.28 ± 1.59 MPa). All the developed materials exhibited bioactivity in vitro. The obtained results shed new light on surfactants as CPCs additives. They should not only be considered as foaming agent or binders, but also they deserve more attention as modifiers affecting the physicochemical properties of α-TCP based materials.

Hollow silica microspheres as robust immobilization carriers.

Hollow silica microspheres provide an ideal solid support for enzyme immobilization. We tested one of the newest development, namely MATSPHERES®, a silica openwork material as a carrier for the covalent immobilization of enzymes used to synthesize bioactive compounds. Two model enzymes - ethylbenzene dehydrogenase and EL070 lipase - were considered. They belong to two different enzyme classes and catalyse reactions taking place in various environments (aqueous and non-aqueous, aerobic and anaerobic). The enzymes were immobilized by covalent bonds (via divinyl sulfone and glutaraldehyde) on new silica material. Effectiveness of immobilization processes on the spheres grafted with amine groups and on the analogues without functionalization was determined for both enzymes. Microspheres were characterized morphologically and also their mechanical stability was examined during exposure to varying physical conditions. It was shown that MATSPHERES® due to their openwork structure and relative stability under batch and flow conditions can be a competitive SBA support for enzyme immobilization and production of bioactive compounds.

Lactose esters: synthesis and biotechnological applications.

Biodegradable nonionic sugar esters-based surfactants have been gaining more and more attention in recent years due to their chemical plasticity that enables the various applications of these molecules. In this review, various synthesis methods and biotechnological implications of lactose esters (LEs) uses are considered. Several chemical and enzymatic approaches are described for the synthesis of LEs, together with their applications, i.e. function in detergents formulation and as additives that not only stabilize food products but also protect food from undesired microbial contamination. Further, this article discusses medical applications of LEs in cancer treatment, especially their uses as biosensors, halogenated anticancer drugs, and photosensitizing agents for photodynamic therapy of cancer and photodynamic inactivation of microorganisms.

Predictors of suicidality among Polish university students during COVID-19 pandemic.

PURPOSE OF REVIEW: The main purpose of the study was to assess university students' mental health and identify factors associated with the risk of suicidal thoughts, plans, and attempts during coronavirus disease 2019 (COVID-19) pandemic and distance learning. RECENT FINDINGS: The study was conducted in spring 2021 and comprised 10 760 Polish students. The survey employed modified versions of the C-SSRS, CIDI, WHO-5, GAD-7, the PTSD checklist for DSM-5 and CAGE-AID Questionnaire and included questions about panic attacks, COVID-19-related information and sociodemographic characteristics. The correlates of suicidality were examined using a series of logistic regression analyses. Almost 40% students experienced any suicidal thoughts and/or behaviours in the previous month: passive ideations only (15.8%), active ideations only (7.1%), plans without attempts (15%), and attempts (1.4%). Following variables were related to the increased risk for suicide attempts: severe anxiety [odds ratio (OR) = 11.39; 95% confidence interval (CI): 1.44-90.26], panic attacks (OR = 3.21; 95% CI: 1.75-5.91), and COVID-19 hospitalisation (OR = 11.04; 95% CI: 1.17-104.59). Major depression was associated with passive and active ideations, suicide plans, but not with attempts (OR = 1.37; 95% CI: 0.45-4.13). SUMMARY: University students present a high level of adverse mental health and increased risk of STBs during COVID-19 pandemic. A suicide prevention program tailored to this population is needed during and after the pandemic.

Anxiety disorders as predictors of suicidality in people with type 2 diabetes mellitus: Findings of a study in six European countries. / Zaburzenia lekowe jako predyktory samobójczosci u osób z cukrzyca typu 2: Wyniki badania przeprowadzonego w szesciu europejskich krajach.

OBJECTIVES: Anxiety disorders are significant predictors of suicidality and are proposed to be independent risk factors for suicide attempts. They are common in people with type 2 diabetes (T2DM) and are associated with longer duration of diabetes and poorer treatment outcomes. The aim was to examine associations between anxiety disorders and suicidal thoughts and behaviour in people with T2DM, to establish the prevalence of suicidality among people with T2DM in the selected European countries and to examine whether anxiety disorders were predictive of current outcomes of suicidality in this population using data from the International Prevalence and Treatment of Diabetes and Depression study. METHODS: The study sample comprised 1063 adults with T2DM from 6 European countries. The presence of anxiety disorders and suicidality was assessed with the MINI International Neuropsychiatric Interview. The group of participants with current suicidal risk was compared with the group of participants with no suicidal risk. RESULTS: The participants from Germany were more likely to report suicidality than those from other countries, whereas people from Serbia and Ukraine were less likely to report it. Depression and anxiety disorders significantly contributed to the increased presence of suicidality among people with T2DM. Agoraphobia was a significant predictor of suicidality when controlling for depression. The participants with T2DM and comorbid agoraphobia had 4.86 times higher odds to report suicidality than those without agoraphobia. CONCLUSIONS: Agoraphobia was a significant predictor of suicidality in people with T2DM.

Evaluation of mental health services delivered before and after the introduction of pilot Mental Health Centers in Poland using monitoring indicators. / Ocena realizacji psychiatrycznych swiadczen zdrowotnych z okresu przed i po wprowadzeniu pilotazowych centrów zdrowia psychicznego w Polsce z wykorzystaniem wskazników monitorujacych.

OBJECTIVES: The study assessed the performance of Mental Health Centres compared to previous non-integrated mental health facilities. METHODS: The study used National Health Fund (NHF) data of individuals over 18 years treated in 27 centres (January 2017 - February 2020). Performance indicators from 19 months before (N = 124,497) and after the introduction of Mental Health Centres (N = 182,789) were compared for outpatient care, community treatment teams, inpatient wards and day wards. RESULTS: The total number of patients who received mental health care increased, compared to before the establishment of those Centres; whereas the number of hospitalisations decreased by 6% and the number of patient days per person decreased by 9%. Day care saw a 14% increase in admissions following the introduction of Mental Health Centres, with a 5% decrease in patient days per person. The proportion of patients in community care increased by 86%, in outpatient care by 62% and in day care by 14%. The number of first-time patients after the introduction of Mental Health Centres increased and the number of follow-up patients decreased. For all groups of mental disorders, the priority indicator in inpatient care decreased, while increasing in outpatient and community care for most groups of disorders. CONCLUSIONS: The results confirmed the effectiveness of the National Mental Health Protection Programme project in relation to the availability and reduction of inpatient treatment through Mental Health Centres. The methodology used in this study can be used for assessing the effectiveness of Mental Health Centre activities in subsequent stages of the pilot.

Social support against depression in young adults' group during COVID-19 pandemic. / Wsparcie spoleczne a przeciwdzialanie depresji w grupie mlodych doroslych w czasie pandemii COVID-19.

OBJECTIVES: The present study aimed at analyzing the prevalence of depressive symptoms in a group of learning young adults, as well as the social support as a predictor of depression in late adolescence during the COVID-19 pandemic. METHODS: An online national survey of young adults attending schools was conducted. The semi-structured questionnaire, including a section on sociodemographic data, stressors, needs and sources of support, as well as brief version of the Kutcher Adolescent Depression Scale, was distributed to young Poles. The final sample consisted of 1,500 students aged 18-23. Multivariable logistic regression assessed the relationships between support needs and sources and depressive symptoms. RESULTS: The support needs that are most commonly reported by young adults are support from loved ones (family, friends) (n = 843; 56.2%) and teachers (e.g., care, appreciation) (n = 603; 40.2%). Fifty-six per cent of Polish young adults are experiencing significant depressive symptoms (95% confidence interval [CI]: 1.82-13.96). Young adults with no social support had higher KADS score than participants reporting some form of support (b = 1.794; 95% BCa CI = 0.659, 2.947). Participants receiving support from mother, both parents and siblings had a lower severity of depressive symptoms, while young people receiving support from father had more severe symptoms. CONCLUSIONS: This study provides initial findings in terms of depressive symptoms and support needs of young adults during the COVID-19 pandemic. It is imperative for mental health services, communities and schools to provide the necessary support to young adults.

Depression among young adults - risks and protective factors in the COVID-19 pandemic.

Purpose: The present study aimed to assess the depression symptoms and predictors of depression in Polish young adults during online learning in the COVID-19 pandemic. Methods: The online questionnaire, including the Kutcher Adolescent Depression Scale, was distributed to young Poles through school principals. The final sample consisted of 1,500 students between the ages of 18 and 23 attending secondary schools. Multivariable logistic regression assessed the relationships between sociodemographic factors, pandemic stressors, coping behaviours and depressive symptoms. Results: 56% of young Polish adults are experiencing significant depressive symptoms (95% CI: 1.82-13.96). Social isolation was recognized as the main stressor. Many significant predictors of depression were captured. Being female, living in the countryside, talking to parents, and participating in sports and hobbies are found to be protective factors. The following sociodemographic factors are important predictors of depression in young adults: being male, attending a secondary school, living in a large city. Experiencing stress due to pandemic and online learning is one of the risk factors for depression. Conclusions: The majority of young Poles met the criteria for depressive disorders. The initial findings of the presented study not only highlight the need to address mental health consequences for young people during online learning, but also provide the grounds for the development of post-pandemic interventions.

Predictors of teachers' mental health - implications for practice.

Purpose: To identify teachers' mental health predictors of stress, anxiety and depression within the sociodemographic, health-related, work-related and COVID-19-related factors. Methods: Between March 3 and April 11, 2021 the cross-sectional national online survey of Polish teachers of all educational levels was conducted. The semi-structured questionnaire used in the study included demographic data (place of residence, gender, age, marital status, education), exposure to people infected with COVID-19, critical life events and pandemic-related stressors, health variables, work-related characteristics (duration of remote teaching), as well as DASS-21. Results: In 2,757 completed responses, 86% of the respondents were female and the mean age was 46.14 (SD = 9.35); 21.3% had been previously diagnosed with COVID-19; 38.8% of the respondents (n = 1,069) were employed in primary schools (grades 4-8) and 34% worked in the secondary level education. The mean years of work experience in the sample was 20.94 (SD = 10.60). At the moment of completing the survey, most of the respondents (n = 1,488; 54%) were working on-site, 24% were still working remotely and 22.1% were engaged in the hybrid model. Sociodemographic variables, mental and physical illness, fear of the negative consequences of COVID-19, and the deaths of a family member or friend due to COVID-19 were significant predictors of stress, anxiety, and depression. Stress and depression were also predicted by remote working methods and working in a very large city. The cases of COVID-19 in groups of co-workers or students predicted only stress. COVID-19 deaths of co-workers/students/parents of students and COVID-19 diagnosis predicted anxiety. Conclusions: The most vulnerable group of teachers turned out to consist in young women, working in a big city, mostly teaching remotely. Sustainable support and care systems adapted to the teachers' needs should be developed. Also some essential predictors of mental health deterioration among teachers should be considered when designing long-term prevention strategies.

Relations of Well-Being, Coping Styles, Perception of Self-Influence on the Diabetes Course and Sociodemographic Characteristics with HbA1c and BMI Among People with Advanced Type 2 Diabetes Mellitus.

PURPOSE: Assessment of the relationship between psychological and sociodemographic factors with the levels of glycated hemoglobin (HbA1c) and Body Mass Index (BMI) among people with advanced type 2 diabetes mellitus (T2DM). PATIENTS AND METHODS: A total of 2574 persons, among them 1381 (53.7%) women, with type 2 diabetes, during the period of switching from biphasic mixtures of human insulin to insulin analogues. The age of participants ranged from 22 to 94 years (M = 63.5; SD = 9.58), and their treatment period was in the time frame from 2 years to 43 years (M = 10.2; SD = 6.1). Participants filled out a Scale for Perception of Self-Influence on the Diabetes Course, Well-Being Index WHO-5, two questions from the Brief Method of Evaluating Coping with a Disease. RESULTS: Statistically significant correlations were found between the HbA1c levels and (1) disease duration (rs=0.067; p < 0.001); (2) number of complications (rs = 0.191, p < 0.001) (3) the perception of self-influence on the diabetes course (rs=- 0.16; p < 0.001); (4) well-being (risk of depression) (rs=- 0.10; p < 0.001). The regression analysis showed that 7% of HbA1c variability is explained by age, a perception of self-influence on the diabetes course, the number of complications, place of residence, education, BMI. The most important findings concerning BMI were found in regression analysis, which indicated a week relationship between BMI and a number of complications, perception of self-influence on the diabetes course and coping styles (3% of the resultes' variability). The group at high risk of depression had the highest levels of HbA1c. CONCLUSION: Sociodemographic and psychological factors show weak but statistically significant relationships with the current levels of HbA1c and BMI.

Association of Higher Rates of Type 2 Diabetes (T2DM) Complications with Psychological and Demographic Variables: Results of a Cross-Sectional Study.

Introduction: The aim of this study was to assess the relationship between the occurrence and number of T2DM complications with sociodemographic (age, sex, habitation, education), clinical (duration of diabetes, HbA1c (%), BMI) and psychological (well-being, sense of influence on the diabetes course, coping styles) variables. Methods: A total of 2574 adult patients were assessed using The Sense of Influence on the Diabetes Course Scale, WHO-5 Well-Being Index, and the Brief Method of Evaluating Coping with Disease. Hierarchical Regression Analysis was conducted with number of complications as the dependent variable and three sets of variables entered in sequential steps: (a) sociodemographic; (b) clinical and (c) psychological factors. Logistic regression analysis was used to examine the association of these variables with diabetes complications' occurrence. Results: A higher number of complications and higher odds ratios of occurrence of complications were associated with sociodemographic and clinical variables, poor well-being, low perception of influence on the diabetes course, and an emotion-oriented coping style. The logistic regression indicated that participants with HbA1c >7% (in comparison with HbA1c ≤ 7%) and with high risk of depression (in comparison with no risk of depression) had respectively 68% and 86% higher odds of developing complications. Discussion: The number of complications has weak but statistically significant relations with psychological and clinical factors. Conclusion: The results support the rationale of including the psychosocial factors in the context of diabetes management.

Influence of Natural Polysaccharides on Properties of the Biomicroconcrete-Type Bioceramics.

In this paper, novel hybrid biomicroconcrete-type composites were developed and investigated. The solid phase of materials consisted of a highly reactive α -tricalcium phosphate (α-TCP) powder, hybrid hydroxyapatite-chitosan (HAp-CTS) material in the form of powder and granules (as aggregates), and the polysaccharides sodium alginate (SA) or hydroxypropyl methylcellulose (HPMC). The liquid/gel phase in the studied materials constituted a citrus pectin gel. The influence of SA or HPMC on the setting reaction, microstructure, mechanical as well as biological properties of biomicroconcretes was investigated. Studies revealed that manufactured cement pastes were characterized by high plasticity and cohesion. The dual setting system of developed biomicroconcretes, achieved through α-TCP setting reaction and polymer crosslinking, resulted in a higher compressive strength. Material with the highest content of sodium alginate possessed the highest mechanical strength (~17 MPa), whereas the addition of hydroxypropyl methylcellulose led to a subtle compressive strength decrease. The obtained biomicroconcretes were chemically stable and characterized by a high bioactive potential. The novel biomaterials with favorable physicochemical and biological properties can be prosperous materials for filling bone tissue defects of any shape and size.

Effect of Gold Nanoparticles and Silicon on the Bioactivity and Antibacterial Properties of Hydroxyapatite/Chitosan/Tricalcium Phosphate-Based Biomicroconcretes.

Bioactive, chemically bonded bone substitutes with antibacterial properties are highly recommended for medical applications. In this study, biomicroconcretes, composed of silicon modified (Si-αTCP) or non-modified α-tricalcium phosphate (αTCP), as well as hybrid hydroxyapatite/chitosan granules non-modified and modified with gold nanoparticles (AuNPs), were designed. The developed biomicroconcretes were supposed to combine the dual functions of antibacterial activity and bone defect repair. The chemical and phase composition, microstructure, setting times, mechanical strength, and in vitro bioactive potential of the composites were examined. Furthermore, on the basis of the American Association of Textile Chemists and Colorists test (AATCC 100), adapted for chemically bonded materials, the antibacterial activity of the biomicroconcretes against S. epidermidis, E. coli, and S. aureus was evaluated. All biomicroconcretes were surgically handy and revealed good adhesion between the hybrid granules and calcium phosphate-based matrix. Furthermore, they possessed acceptable setting times and mechanical properties. It has been stated that materials containing AuNPs set faster and possess a slightly higher compressive strength (3.4 ± 0.7 MPa). The modification of αTCP with silicon led to a favorable decrease of the final setting time to 10 min. Furthermore, it has been shown that materials modified with AuNPs and silicon possessed an enhanced bioactivity. The antibacterial properties of all of the developed biomicroconcretes against the tested bacterial strains due to the presence of both chitosan and Au were confirmed. The material modified simultaneously with AuNPs and silicon seems to be the most promising candidate for further biological studies.

Development of highly porous calcium phosphate bone cements applying nonionic surface active agents.

A novel way of obtaining highly porous cements is foaming them with the use of nonionic surface active agents (surfactants). In this study, foamed calcium phosphate cements (fCPCs) intended for in situ use were fabricated by a surfactant-assisted foaming process. Three different surface active agents, Tween 20, Tween 80 and Tetronic 90R4, were used. The amount of surfactant, based on its critical micelle concentration and cytotoxicity as well as foaming method, was determined. It has been established that in order to avoid cytotoxic effects the concentration of all applied surfactants in the cement liquid phases should not exceed 1.25 g L-1. It was found that Tetronic 90R4 had the lowest cytotoxicity whereas Tween 20 had the highest. The influence of the type of surfactant used in the fabrication process of bioactive macroporous cement on the physicochemical and biological properties of fCPCs was studied. The obtained materials reached higher than 50 vol% open porosity and possessed compressive strength which corresponds to the values for cancellous bone. The highest porosity and compressive strength was found for the material with the addition of Tween 80. In vitro investigations proved the chemical stability and high bioactive potential of the examined materials.