The
field of photodynamic therapy (PDT) has continued to show promise
as a potential method for treating tumors. In this work, a photosensitizer
(PS) has been delivered to cancer cell lines for PDT by incorporation
into the metal–organic framework (MOF) as an organic linker.
By functionalizing the surface of MOF nanoparticles with maltotriose,
the PS can efficiently target cancer cells with preferential uptake
into pancreatic and breast cancer cell lines. Effective targeting
overcomes some current problems with PDT including long-term photosensitivity
and tumor specificity. Developing a PS with optimal absorption and
stability is one of the foremost challenges in PDT, and the synthesis
of a chlorin, which is activated by long wavelength light and is resistant
to photobleaching, is described. This chlorin-based MOF shows anticancer
ability several times higher than that of porphyrin-based MOFs with
little toxicity to normal cell lines and no dark toxicity.
Metal–organic frameworks (MOFs) are a well‐suited platform for drug delivery systems that can affect photodynamic therapy (PDT). A well‐designed PDT delivery system to treat cancer can overcome some problems of current PDT such as prolonged photosensitivity and tumor specificity. Triple negative breast cancer (TNBC) is difficult to treat with existing chemotherapy and often requires surgery because it quickly metastasizes throughout the body. Tumor associated macrophages (TAM) are known to be M2‐like macrophages, which are involved in processes of cancer progression, such as angiogenesis, matrix remodeling, and metastases. These roles are brought on by the expression of the CD206 (mannose receptor) on the surface of the macrophage. MOF nanoparticles around 50 nm are synthesized by a solvothermal reaction of Mn(III)‐tetrakis(4‐carboxyphenyl) porphyrin, tetrakis(4‐carboxyphenyl) porphyrin, and ZrOCl2. Through postsynthetic modification, Zn(II) is incorporated into the tetrakis(4‐carboxyphenyl) porphyrin sites and potassium maltotrionate is conjugated with the empty coordination sites on the Zr6O4(OH)4 clusters. The resultant maltotriose‐PCN‐224‐0.1Mn/0.9Zn is able to specifically target tumor cells and TAM. Upon irradiation by a light‐emitting diode (LED) source, TNBC and the TAM cells were selectively targeted by MA‐PCN‐224‐0.1Mn/0.9Zn via the glucose transporter (GLUT) and CD206 receptors. The MA‐PCN‐224‐0.1Mn/0.9Zn shows no toxicity toward normal cell lines and no dark toxicity.
An efficient and rapid method has been established for micron cellulose (1, 20 microns) oxidation utilizing Oxone ® (KHSO 5) in combination with 2,2,6,6-tetramethylpiperidinyl-1-oxyl (TEMPO) and NaOCl in aqueous NaHCO 3 solution (pH 7.5 to 8.5) under microwave irradiation. This method affords two different forms of nano TEMPO-cellulose, i.e. a water-insoluble form (Form-I, 14 nm) and a water-soluble form (Form-II, 8 nm). Cellulose oxidation utilizing this Oxone ® methodology has advantages over other methodologies, which include low cost and formation of two nano TEMPOcellulose forms over a rapid reaction time utilizing microwave irradiation conditions. TEMPOcellulose forms were characterized by FT-IR, NMR, solid state 13 C-NMR and by elemental analysis. The TEMPO-cellulose forms morphology was studied by SEM analysis. The average fiber width and length of TEMPO-cellulose materials was determined in nanometer range by TEM analysis and the surface charge was identified by zeta potential.
Cellulose nanocrystals (CNCs) have shown promise for the development of multifunctional materials for many research communities, ranging from bioresource engineering and biomedical engineering to materials science and engineering. However, accessible hydroxyl (OH) groups on the surface of colloidal CNCs at the (11̅ 0)β/(100)α and (110)β/(010)α facets and the intermolecular hydrogen bonding (H-bonds) between these OH groups account for the instability of self-assembled CNC structures in moist environments, limiting their practical uses to dry media. In this work, accessible OH groups of CNCs were crosslinked using two crosslinkers, that is, glutaraldehyde (GA) and epichlorohydrin (EC), to form nanoparticle-based hydrogels with tunable physicochemical properties. The intensity of the intermolecular H-bonds was controlled by the type and concentration of crosslinkers as well as the CNC concentration. Rheological analyses through the loss tangent were used to determine the degree of crosslinking with maximal values beyond 90%. Fourier-transform infrared spectroscopy demonstrated that H-bond intensity was inversely proportional to the degree of crosslinking for both GA and EC, indicating a dissimilar crosslinking mechanism for GA and EC in acidic and alkaline pH conditions, respectively. Atomic force microscopy and wettability analyses showed a significant increase in the surface roughness from 3.2 ± 0.41 nm (pure CNC) to 31.5 ± 1.08 nm (CNCs crosslinked by GA) and 23.8 ± 0.14 nm (CNCs crosslinked by EC) and water contact angle from 13°(pure CNC) to 108°(CNCs crosslinked by GA) and 104°(CNCs crosslinked by EC). Moreover, optimum water absorption values were found at 157.67 ± 2.01 g and 173.59 ± 1.26 g of water for 1 g of freeze-dried hydrogels for 10% GA and 1% EC, respectively. The results aligned with reaction conditions that led to maximal degrees of crosslinking and indicated the transformation of surface chemistry from a hydrophilic to a hydrophobic network as well as tunable topology and aqueous stability of self-assembled structures made from crosslinked CNCs. This technology demonstrated the potential of crosslinked CNCs with tunable physicochemical properties for use as advanced building blocks to produce 2D and 3D structures for their related functions.
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