Preparation Of Silicon-Based Functional Nanomaterials And Their Application For Cancer Diagnosis And Therapy

Up to now,although biomedical and clinical technology have made tremendous progress,cancer as one of the deadliest diseases around the world still threatens human health.To this end,scientists have developed high-performance nanosystems for early diagnosis and treatment of cancer.During the past few decades,the surgical resection,chemotherapy,radiotherapy,and immunotherapy based on varieties of functional nanomaterials have been developed.Among them,the surgical resection as one of the trational manner of clinical cancer therapy has made sufficient progress,while the postoperative tumor recurrence and bacterial infection of surgical wounds still threaten human health.Scientists have further utilized functional nanomaterials to construct various therapeutic systems to inhibit postoperative tumor regeneration and bacterial infections.In recent years,taking advantages of large specific surface area,unique electronic/optical/mechanical properties,easy surface modifiability,and good biocompatibility,silicon-based functional nanomaterials have attracted extensive interests in the field of cancer diagnosis and therapy.It is worth noting that previous studies mainly focused on developments of silicon-based nanomaterials featuring single function,which could be utilized for bioimaging analysis/detection or treatment of tumor-related diseases.Therefore,developments of multi-functional silicon-based nanomaterials,which are capable of simultaneous diagnosis and treatment of tumors,become a major research hotspot up to present.This dissertation intends to develop multifunctional silicon-based nanomaterials for tumor diagnosis and treatments.Firstly,we produce silicon-based nanomaterials suitable for cellular imaging or tumor treatment,respectively.Secondly,we synthesize dual-functional silicon-based nanomaterials suitable for simultaneous tumor imaging and therapy.Finally,we develop silicon-based multifunctional nanomaterial,which is workable for cell imaging,cancer therapy,and anti-bacterial infection in simultaneous manners.This dissertation includes the following chapters:Chapter 1:We firstly give a brief introduction of cancers as well as the importance of early detection and treatments of cancers.Secondly,we briefly review representative progress of synthesis of silicon-based nanomaterials and their application for cancer diagnosis and therapy.Finally,we introduce the research basis and significance of this thesis,as well as the research content of this dissertation.Chapter 2:We develop silicon-based nanomaterials for tumor cell imaging.In details,by using four kinds of tea extracts(e.g,Green tea,Black tea,Oolong tea,or Puer tea)and organosilane as precursors,we prepare silicon-based nanomaterials under microwave reaction for tumor cell imaging.The resultant silicon nanoparticles(SiNPs)feature the excitation wavelength-dependent fluorescent spectra.In particular,the maximum emission wavelength of such resultant SiNPs is red-shift significantly with the gradual increase of excitation wavelength.In addition,the as-prepared SiNPs feature strong fluorescence,good photostability,and favorable biocompatibility.Such high-performance SiNPs are further modified with the functional IgG molecules,and then used for the immunofluorescent imaging of cellular nucleus.Chapter 3:We develop silicon-based nanomaterials for imaging intracellular pH in living tumor cells.In details,by selecting europium trichloride,fresh milk,trisodium citrate,and organosilane as precursors,we fabricate silicon nanorods-based pH sensor in microwave-assisted reaction,which can detect intracellular pH.Such sensor shows two fluoescent peaks under the irradiation of 405 nm.Those are blue fluorescence with the maximum emission wavelength of 470 nm,and red fluorescence with the maximum emission wavelength of 620 nm.Among them,blue fluorescence signals of sensors can produce obvious response to pH change,while red fluorescence signals are relatively stable.Therefore,the change of pH can be quantitatively detected by comparing fluorescence intensity of blue fluorescence signal and red fluorescence signal.We further demonstrate that the prepared sensor features stable photostability,specific pH detection,and good biocompatibility,thus suitable for monitoring the dynamic changes of pH in living tumour cells.Chapter 4:We develop a kind of silicon-based nanomaterials for cancer therapy.In details,we construct silicon nanowires-based synergetic therapeutic system,which is made of silicon nanowires(SiNWs)and doxorubicin(DOX).Lactate dehydrogenase assay and propidium iodide imaging results confirm that the SiNWs can effectively destroy cell membrane of breast cancer cells and further change their permeability.The SiNWs thus can promote DOX to enter into cancer cells through destroying the cell membrane.Furthermore,the intracellular SiNWs and DOX are able to induce the destruction of cellular cytoskeleton,and further damage mitochondria to release the cytochrome Cinside.Cell cycle distribution indicates that SiNWs and DOX are able to inhibit cell cycle at G2 phase.The combined index(CI)of SiNWs and DOX is calculated to be?0.56(<1)through statistical analysis.Chapter 5:We develop silicon-based dual-functional nanomaterials for cell imaging and cancer therapy.In details,by choosing four kinds of green teas(i.e.,Anji white tea,Longjing,Gougunao,and Biluochun tea)and organosilane as precursors,we prepare silicon-based dual-functional nanomaterials assisted by microwave irradiation,which is suitable for simultaneous cell imaging and cancer therapy.Different green teas and organosilicane are able to produce dual-functional silicon-based nanomaterials with controllable zero-(e.g.,nanoparticles),two-(e.g.,nanosheets),and three-(e.g.,nanospheres)dimensional nanostructures.The as-prepared green tea-originated silicon nanomaterials(GTSN)are not only useful for imaging cellular nuclei,but also efficacious for killing tumor cells.We further demonstrate that the dual-functional GTSN is avialable for long-term in vivo imaging of tumour tissues and efficient inhibition of tumour growth.Chapter 6:We develop silicon-based multifunctional nanomaterials for cell imaging,cancer therapy,and anti-bacteria in simultaneous manners.In details,the Caulis Spatholobi-originated SiNPs(CS-SiNPs)featuring good fluorescent property,anti-cancer,and anti-bacterial activity are prepared through selecting TCM extracts and organosilane as reaction precursors under microwave irradiation.The resultant CS-SiNPs possess good aqueous dispersibility,strong fluorescence,and good photostability,suitable for fluoescence imaging of cellular nuclei.We further reveal that the CS-SiNPs simultaneously feature anti-tumorous activity and anti-bacterial effects.We also demonstrate that the as-prepared multifunctional CS-SiNPs are effective for inhibiting the postoperative recurrence of tumor tissues and anti-bacterial infectionsChapter 7:We firstly summarize the research achievements in the synthesis of mutifunctional silicon-based nanomaterials and their applications for cancer diagnosis and therapy.Secondly,we briefly introduce the innovative points of this research,and then discuss shortcomings of this current study.Finally,we introduce future prospects of silicon-based nanomaterials for tumor diagnosis and treatments.In summary,this dissertation focuses on the development of single/double/triple functional silicon-based nanomaterials,which are useful for tumor imaging,cancer therapy,and anti-bacteria application.The presented results in this dissertation are potentially important for the development of silicon-based nanomaterials for cancer diagnosis and treatment.