The introduction of 3D bioprinting is expected to revolutionize the field of tissue engineering and regenerative medicine. The 3D bioprinter is able to dispense materials while moving in X, Y, and Z directions, which enables the engineering of complex structures from the bottom up. In this study, a bioink that combines the outstanding shear thinning properties of nanofibrillated cellulose (NFC) with the fast cross-linking ability of alginate was formulated for the 3D bioprinting of living soft tissue with cells. Printability was evaluated with concern to printer parameters and shape fidelity. The shear thinning behavior of the tested bioinks enabled printing of both 2D gridlike structures as well as 3D constructs. Furthermore, anatomically shaped cartilage structures, such as a human ear and sheep meniscus, were 3D printed using MRI and CT images as blueprints. Human chondrocytes bioprinted in the noncytotoxic, nanocellulose-based bioink exhibited a cell viability of 73% and 86% after 1 and 7 days of 3D culture, respectively. On the basis of these results, we can conclude that the nanocellulose-based bioink is a suitable hydrogel for 3D bioprinting with living cells. This study demonstrates the potential use of nanocellulose for 3D bioprinting of living tissues and organs.

Bacterial nanocellulose (BNC), synthesized by the bacterium Gluconacetobacter xylinus, is composed of highly hydrated fibrils (99 % water) with high mechanical strength. These exceptional material properties make BNC a novel biomaterial for many potential medical and tissue engineering applications. Recently, BNC with cellulose content of 15 % has been proposed as an implant material for auricular cartilage replacement, since it matches the mechanical requirements of human auricular cartilage. This study investigates the biocompatibility of BNC with increased cellulose content (17 %) to evaluate its response in vitro and in vivo. Cylindrical BNC structures (Ø48 × 20 mm) were produced, purified in a built-in house perfusion system, and compressed to increase the cellulose content in BNC hydrogels. The reduction of endotoxicity of the material was quantified by bacterial endotoxin analysis throughout the purification process. Afterward, the biocompatibility of the purified BNC hydrogels with cellulose content of 17 % was assessed in vitro and in vivo, according to standards set forth in ISO 10993. The endotoxin content in non-purified BNC (2,390 endotoxin units (EU)/ml) was reduced to 0.10 EU/ml after the purification process, level well below the endotoxin threshold set for medical devices. Furthermore, the biocompatibility tests demonstrated that densified BNC hydrogels are non-cytotoxic and cause a minimal foreign body response. In support with our previous findings, this study concludes that BNC with increased cellulose content of 17 % is a promising non-resorbable biomaterial for auricular cartilage tissue engineering, due to its similarity with auricular cartilage in terms of mechanical strength and host tissue response.

Bacterial nanocellulose (BNC) is a 3D network of nanofibrils exhibiting excellent biocompatibility. Here, we present the aqueous counter collision (ACC) method of BNC disassembly to create bioink with suitable properties for cartilage-specific 3D-bioprinting. BNC was disentangled by ACC, and fibril characteristics were analyzed. Bioink printing fidelity and shear-thinning properties were evaluated. Cell-laden bioprinted grid constructs (5 × 5 × 1 mm3) containing human nasal chondrocytes (10 M mL–1) were implanted in nude mice and explanted after 30 and 60 days. Both ACC and hydrolysis resulted in significantly reduced fiber lengths, with ACC resulting in longer fibrils and fewer negative charges relative to hydrolysis. Moreover, ACC-BNC bioink showed outstanding printability, postprinting mechanical stability, and structural integrity. In vivo, cell-laden structures were rapidly integrated, maintained structural integrity, and showed chondrocyte proliferation, with 32.8 ± 13.8 cells per mm2 observed after 30 days and 85.6 ± 30.0 cells per mm2 at day 60 (p = 0.002). Furthermore, a full-thickness skin graft was attached and integrated completely on top of the 3D-bioprinted construct. The novel ACC disentanglement technique makes BNC biomaterial highly suitable for 3D-bioprinting and clinical translation, suggesting cell-laden 3D-bioprinted ACC-BNC as a promising solution for cartilage repair.

SUMMARY. Tetranectin (TN), a new regulator of fibrinolysis, was studied in the plasma of 60 patients with acute myocardial infarction (AMI) and 30 healthy subjects (HS), in relation to D-dimer (DD) and a2-plasmin inhibitor (Q-PI), to investigate its possible involvement in the pathophysiology of AMI. Thirty patients underwent thrombolytic treatment with fibrin-specific plasminogen activator (rt-PA) (group A); the other 30 patients, according to the exclusion criteria, were conventionally treated (group B). Twenty of the thrombolysized patients established early recanalization (subgroup A,), while 10 failed to respond to thrombolytic treatment (subgroup A*). Median (interquartile range), baseline plasma T N levels were lower in AM1 patients compared to HS [8.27 (2.75) mg/L versus 12.1 (0.55) mg/ L, P < lo-']. In subgroup A , , TN increased at the end of rt-PA infusion and returned to the baseline levels 12 h later. A positive association between D D and T N release (3 h level minus baseline level) was found (r,=O.48, P=O.O3) in subgroup A,. No significant alterations of T N levels were observed during therapy in subgroup A2 and group B. TN, DD and Q-PI concentrations in group B remained relatively constant during the study period. This study provides evidence of a significant decrease of T N levels in AM1 patients compared to healthy subjects and of a remarkable difference in the evolution of T N levels during thrombolytic treatment with rt-PA between recanalized and non-recanalized AM1 patients. Thus, an involvement of T N in the formation and dissolution of fibrin clot in AM1 patients is worthy of further investigation. Additional key phrases: recanalization; D-dimer; cc2-plasmin inhibitor; jibrin-specijic plasminogen activatorThe beneficial effects of thrombolysis in the treatment of acute myocardial infarction (AMI) are now well established.' Early thrombolytic treatment results in reperfusion of the occluded coronary artery in 6&70% of cases.2 Despite early treatment with fibrin-specific plasminogen activator (rt-PA) reperfusion cannot be achieved in all patients and according to a considerable number of studies 15-30% of the patients fail to respond.'-5 Failure of thrombolysis may be explained by the activation of both fibrinolytic and coagulation systems during treatment.6

Drugs are lately considered high-risk factors for cerebrovascular disease. Three male patients (mean age 24.6 years) who were heavy cannabis smokers presented with transient ischemic attacks (TIA) shortly after cannabis abuse. The complete examination of all 3 consisted of: EEG, brain CT scan, brain MRI, cerebral vessel angiography (digital subtraction and magnetic resonance angiography); also a full cerebrospinal fluid, urine and blood analysis (immunological, biochemical and hormonal tests were included). Urine was further examined for drug metabolites. An extensive cardiological investigation was carried out. Small vessel leukoencephalopathy was revealed by the brain CT and MRI. EEG recordings of the first patient showed paroxysmal sharp waves with left hemispheric dominance. The other 2 patients had diffuse delta and theta activity in their EEG tracings. The urine analysis was positive for cannabis metabolites. There were no other abnormal findings in the rest of the meticulous and thorough study of all 3 patients, which leads to the conclusion that cannabis was the only risk factor responsible for the observed TIA, contradictory to other studies, which support that cannabis is a ‘safe’ drug. More research is required in order for this issue to be completely elucidated.

Human intravenous immunoglobulin (IVIG) is a highly valuable plasma-derived biotherapeutic with several important clinical indications in primary and acquired immunodeficiencies as well as autoimmune diseases, especially neuropathies. Ensuring the viral safety of plasma-derived products, such as human IVIG, is mandatory. Viral filtration is commonly used to affect viral removal in the manufacture of plasma products. Viral filtration of large volumes of a IVIG feed solution can take significant time, the required filter area can be large, and the resultant total cost of filtration is considerable. Therefore, there is a need for a high-capacity filter, which can process large volumes of plasma-derived biotherapeutic products within a short time at reduced cost. Here, we describe for the first time the performance of a nanocellulose-based virus removal filter paper in the processing of human IVIG, which has the potential to address the above-stated issues. The filter exhibited 5–6 log virus clearance of ΦX174 (28 nm; pI 6.6) or MS2 (27 nm; pI 3.9) phages during the filtration of spiked IVIG solutions (11 mg/mL, pH 4.9). To simulate real-life production conditions, filtration at 288 L/m2, corresponding to 3 kg of protein/m2, at 3 bar was undertaken. No substantial filter fouling was evident, with the flux remaining stable throughout filtration at 20–30 L/m2·h. The predicted volumetric capacity V max was ≥1700 L/m2, which corresponds to the processing of ≥19 kg/m2 of immunoglobulins. A number of characterization tests encompassing size-exclusion high-pressure liquid chromatography, dynamic light scattering, and polyacrylamide gel electrophoresis confirmed immunoglobulin integrity before and after filtration. This study has shown that a mille-feuille filter paper manufacturing process offers the possibility of producing cost-efficient viral removal filters with the required performance capabilities suitable for the processing of plasma-derived immunoglobulins and recombinant monoclonal antibodies.

The formulation of arylpropionic acid derivatives (profens), which are poorly soluble Biopharmaceutical Classification System (BCS) Type II drugs, has a strong impact on their therapeutic action. This article shows that heat-treated powder mixtures of free acid profens with high surface area Cladophora cellulose induces drug amorphization and results in enhanced solubility and bioavailability. Similar mixtures produced using conventional low surface area cellulose, i.e., microcrystalline cellulose, does not produce the same effect. The concept is thoroughly described and links the solid-state characterization data, such as differential scanning calorimetry, X-ray powder diffraction, and Fourier-transform infra-red spectroscopy, with in vitro dissolution in biorelevant media and in vivo pharmacokinetic analysis in rats. The concept is demonstrated for several substances from the profens group, including ibuprofen (main model drug), ketoprofen, flurbiprofen, and naproxen. The presented approach opens new ways to produce solid dosage forms of profen drugs in their free acidic form as alternatives to existing analogues, e.g., drug-salt conjugates or soft gel liquid capsules.

Nifedipine (NIF) is a 1,4-dihydropyridine-based calcium channel blocker with poor solubility, whose bioavailability is highly dependent on the type of formulation. Dry powder mixtures of 20% w/w NIF with microcrystalline cellulose (MCC) and its high surface area nanocellulose analogue, which is namely Cladophora (CLAD) cellulose, were produced by heating at the melting temperature of the drug for 1 h. Non-heated samples were used as a reference. The solid-state properties of the mixtures were characterized by scanning electron microscopy, differential scanning calorimetry and X-ray diffraction. The drug release was studied in biorelevant media, including simulated gastric fluid (SGF), fasted-state simulated intestinal fluid (FaSIF) and fed-state simulated intestinal fluid (FeSIF). An enhanced apparent solubility and faster dissolution rate of NIF were observed in the heated mixture of NIF with CLAD-H in all tested biorelevant media (i.e., SGF, FaSIF and FeSIF), which was due to NIF amorphization in the high surface area nanocellulose powder. Ordinary MCC, which is essentially non-porous, did not produce an enhancement of a similar magnitude. The results of the study suggest that dry powder formulation using high surface area nanocellulose is a facile new strategy for formulating calcium channel blocker drugs, which could potentially be a viable alternative to currently used soft gel liquid capsules.